A new approach for commutation torque ripple reduction of FPGA based brushless DC motor with outgoing phase current control

Brushless Direct Current Motor (BLDC) has been deployed across several kinds of applications. However, attaining a smooth torque ripple with fast response is relatively tough, as usually this is based on the varied slew rate line current in the commutation period. Hysteresis Current control has been widely used in earlier works for the maintaining incoming and outgoing phase current at the same rate throughout the commutation period. Additionally, this also helps in reducing the commutation torque ripple and delivers successful commutation. The proposed work here uses a relatively simple control technique that is primarily derived on the basis Outgoing-phase Current Discharge Hysteresis Control (OCDHC). This has been characterized to produce low response time and reduced torque ripple which has been suggested to execute in both conduction and commutation intervals. For the implementation of digital controller, we chose Xilinx Spartan 6 FPGA board. The digital controller algorithm is written using VHDL and is dumped on the FPGA. For this purpose we use Xilinx ISE and iMPACT tools. FPGA receives hall sensor output and current from BLDC motor with reduced torque ripple and generates the gate pulses which drive the IGBT switches using OCDHC control. This condition shows that the performance of the system is not primarily based on the motor parameters, excluding the stator resistance. Lastly, results obtained from the simulation and experimental results validate the significance of the proposed control technique based on response time at load conditions that vary at different junctures.     

Commutation Torque Ripple Suppression in Three Phase Brushless DC Motor Using Open-end Winding

Three phase brushless DC motor has the characteristics of high power density, simple structure and excellent speed regulation performance, which is widely used in the field of electric drive. Open-end winding brushless DC motor has no neutral point, and each phase winding is electrically isolated, which can realize the independent control of each phase winding. Compared with Y-connected brushless DC motor, the open-end winding brushless DC motor has a wider range of speed regulation under the same voltage, and has certain fault-tolerant performance, which is suitable for the application of low voltage and large current. Compared with the multiphase fault-tolerant motor, open-end winding brushless DC motor has simpler structure and higher winding utilization rate. However, the open-end winding brushless DC motor still has torque ripple, among which the cogging torque is related to the motor body structure, while commutation torque ripple is affected by the mutual inductance of the winding and the current freewheeling loop. The commutation process of the open-winding brushless DC motor is analyzed, and it is concluded that the current change rates of the turn-off phase and turn-on phase are equal under the ideal back electromotive force(back-EMF), which can ensure that the non-commutation phase current and the electromagnetic torque kept constant. The overlapping commutation with phase current closed-loop method is proposed to suppress the commutation torque ripple of open-end winding BLDC motor, and the applied voltage on turn-off phase and delayed time of turn-off phase in overlapping commutation are derived, the sliding mode observer is used to calculate the electromagnetic torque. MATLAB simulation and experimental results verify the effectiveness of this method.

     

基于动态换向策略的开关磁阻电机控制方法

针对开关磁阻电机(SRM)的自身结构造成的转矩脉动问题以及驱动系统的抗干扰能力,提出了一种基于改进的动态换向策略与改进小波神经网络(WNN)的控制器方案。基于直接瞬时转矩控制(DITC)系统设计了一种动态的换向策略,减少关断以后的相电流,增加开通相电流的被激励程度,进而抑制系统的转矩脉动。此外基于小波神经网络改进了速度控制器,并将系统的输出转矩引入,使得系统能更好地应对扰动,增强系统的鲁棒性。仿真结果表明,与传统直接瞬时转矩控制和基于小波神经网络的转矩控制相比,转矩脉动减少了22.12％到64.14％,负载突变后静态误差仅为0.02r/min到0.01r/min,可以有效减弱转矩脉动且系统的抗扰能力显著提高。     

无刷直流电机转矩脉动抑制研究

在电力电子技术发展的研究中,无刷直流电机系统具有转矩电流比高、转速高、动态性能好、可靠和易于控制等优点,在中小功率驱动场合应用广泛;但缺点是换相转矩脉动大,一定程度上制约了无刷直流电机的应用。为提高电机精度和稳定性,针对无刷直流电机换相转矩脉动的问题,采用补偿方法,分析了HPWM-LON调制方式对无刷直流电机换相转矩脉动的影响,提出了一种直接面向转矩脉动的补偿方法,建立了Psp ice仿真模型,通过对仿真结果的分析和比较,得出了这种转矩脉动补偿方法能有效的抑制转距的脉动,提高性能精度,消除了转矩脉动产生的噪音。     

基于转矩分配函数的开关磁阻电机的效率优化方法

开关磁阻电机使用传统的转矩分配函数(TSF)控制时虽然可以起到一定的抑制转矩脉动的作用,但却由于换相阶段电流峰值过高,电流可控性下降等问题使得其在换相阶段出现较为明显的转矩脉动,以及较高的铜耗。针对这一问题,提出了一种基于TSF的开关磁阻电机的效率优化方法。将电机特性作为约束条件,以铜耗为优化目标建立最优化模型,利用多重嵌套的遗传算法将该最优化模型应用于Simulink仿真中,得到不同参数下最优的电流参考曲线。再根据不同转速下对电机性能的需求,进一步筛选权重参数,从而得到最优的电流参考曲线。仿真和实验结果表明,该方法能够有效地降低换相阶段的电流峰值、降低电流控制难度,进而在较低转速下抑制转矩脉动、在较高转速下提高效率。     

ANFIS based multi-sector space vector PWM scheme for sensorless BLDC motor drive

This paper presents a design and development of Multi Sector Space Vector Pulse Width Modulation scheme (MS-SVPWM) for the speed control of brushless direct current (BLDC) motor drive. This control scheme is developed to enhance the performance of BLDC under wide range of speed and load variation. The hardware prototype is developed for 400 W, 30 V, 3000 rpm BLDC motor. The drive consists of uncontrolled rectifier unit for providing DC source to inverterunit. The proposed drive control has been done by implementing MS-SVPWM scheme using ANFIS control. The main function of ANFIS controller is to select the suitable sector for the drive and also predict the mismatching pulses by comparing conventional SVPWM and MS-SVPWM switching patterns. This new switching control technique helps to reduce switching losses of inverter and also improves an efficiency of BLDC system. This MS-SVPWM reduces the DC voltage ripple; Total Harmonic Distortion (THD) and torque ripple to the standard level. To verify and validate the practicality of the proposed system, the simulation is first performed using MATLAB Simulink tool. The hardware system is developed for the MS-SVPWM using DSPIC30F4011controller, the simulation and experimental results are presented.     

A new robust speed-sensorless control strategy for high-performance brushless DC motor drives with reduced torque ripple

This paper presents an analysis, design, and strategy of a high-performance speed-sensorless control scheme for estimating the phase-to-phase trapezoidal back-EMF of BLDC motor drive by means of a novel stochastic deconvolution technique in the H_∞ setting, named robust stochastic H_∞ deconvolution filter. In the proposed method, unlike the conventional observer-based approaches, the back-EMF is considered as an unknown input, and no need is felt for the constancy assumption of the rotor position and speed of machine within a short period of the time in the modeling of the BLDC motor which leads to ignoring the back-EMF dynamic at high and variable speed. In addition, since high-speed operation is vital for the motor, an improved approach has also been proposed to reduce the commutation-torque-ripple at high-speed for direct torque control (DTC) strategy of three-phase BLDC motor with 120° conduction mode in parallel with the proposed method due to the fact that drive performance intensely downgrades in this mode.     

Reduction of torque ripple and mechanical vibration of spindle motors in hard-disk drives using a sinusoidal driver

Mechanical vibration and acoustic noise are major obstacles in the development of high-density and high-spindle-speed hard disk drives. Torque ripple caused by the electrical driver is the main source of vibration and noise. This paper proposes a novel driver for spindle motors in hard disk drives based on the principle of position sensorless vector control. To reduce torque ripple, the proposed driver feeds the spindle motor in sinusoidal driving mode by which the sinusoidal current of the motor can be obtained. Experimental results of the proposed driver demonstrate the better driving performance in startup condition and fine sinusoidal current in steady state. Vibration testing shows significant improvement in the attenuation of vibration: the dominant vibration modes can be reduced to one tenth compared to that of a conventional driver. In addition, the mechanism of inducing torque ripple from time-harmonic currents is analyzed and the relationship between induced torque ripple and exhibited vibration modes is examined.     

Reduction of torque ripple and mechanical vibration of spindle motors in hard-disk drives using a sinusoidal driver

Mechanical vibration and acoustic noise are major obstacles in the development of high-density and high-spindle-speed hard disk drives. Torque ripple caused by the electrical driver is the main source of vibration and noise. This paper proposes a novel driver for spindle motors in hard disk drives based on the principle of position sensorless vector control. To reduce torque ripple, the proposed driver feeds the spindle motor in sinusoidal driving mode by which the sinusoidal current of the motor can be obtained. Experimental results of the proposed driver demonstrate the better driving performance in startup condition and fine sinusoidal current in steady state. Vibration testing shows significant improvement in the attenuation of vibration: the dominant vibration modes can be reduced to one tenth compared to that of a conventional driver. In addition, the mechanism of inducing torque ripple from time-harmonic currents is analyzed and the relationship between induced torque ripple and exhibited vibration modes is examined.

     

Improved torque performance in BLDC-motor-drive through Jaya optimization implemented on Xilinx platform

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.     

Noise and vibration due to rotor eccentricity in a HDD spindle system

This paper numerically and experimentally investigates the characteristics of torque ripple and unbalanced magnetic force (UMF) due to rotor eccentricity and their effects on noise and vibration in a hard disk drive (HDD) spindle motor with 12 poles and 9 slots. The major excitation frequencies of a non-operating HDD spindle system with rotor eccentricity are the least common multiples (LCM) of pole and slot numbers of the cogging torque and the harmonics of slot number ±1 of the UMF. An experimental setup is developed to measure the UMF generated by rotor eccentricity and to verify the simulated UMF. In the operating HDD spindle motor, the harmonics of the commutation frequency of torque ripple (multiplication of pole and phase) are increased by the interaction of the driving current and rotor eccentricity, and they are the same as the LCM of pole and slot numbers for a HDD spindle motor with 12 poles and 9 slots. The major excitation frequencies of the UMF while operating condition are also the harmonics of slot number ±1 and the harmonics of commutation frequency ±1. We verify that the source of the harmonics of slot number ±1 and the harmonics of commutation frequency ±1 in acoustic noise and vibration is rotor eccentricity of the UMF through experiments.     

直流无刷电机的DSP模糊控制系统

基于DSP设计了直流无刷电机的模糊控制系统,阐述了系统硬件主电路设计,以及软件实现的设计方法,为解决直流无刷电机控制中难题,进一步提高系统控制性能,采用了无刷直流电机电流、转速双闭环控制及模糊自整定PI算法的控制策略,较好实现了直流无刷电机控制系统的智能控制。应用了PWM控制的重叠换相法抑制转矩脉动。实验结果及仿真结果表明,该系统控制效果良好,转矩脉动抑制明显,运行可靠的特点,验证了该设计的快速稳定和鲁棒性。     

Novel bacterial foraging-based ANFIS for speed control of matrix converter-fed industrial BLDC motors operated under low speed and high torque

In this paper, a novel adaptive neuro-fuzzy inference system (ANFIS)-based control technique optimized by Bacterial Foraging Optimization Algorithm for speed control of matrix converter (MC)-fed brushless direct current (BLDC) motor is presented. ANFIS is considered to be one of the most promising technologies for control of electrical drives fed by MC. Optimizing the training parameters of ANFIS, to improve its performance, is still being considered by several researchers recently. Parameters of the online ANFIS controller such as learning rate (η), forgetting factor (λ) and steepest descent momentum constant (α) are optimized by using the proposed algorithm. For the purpose of comparison, proportional integral derivative controller, fuzzy logic controller, PSO-ANFIS and BAT-ANFIS are considered. Set point tracking performances of the proposed system are carried out at various operating points for an industrial BLDC motor operating at a maximum rated speed of 380 rpm and torque of 6.4 N m. Time domain specifications such as rise time, settling time, peak time, steady-state error and peak overshoot in the presence and absence of load torque disturbances are presented. Time integral performance measures such as integral square error, integral absolute error, and integral time multiplied absolute error are analyzed for various operating conditions. Speed fluctuation in the output of BLDC motor is dependent on the source current harmonics of the inverter/converter. To illustrate this, total harmonic distortion (THD) analysis is carried out for the existing PWM inverter and the proposed MC, and it is proved that MC results in reduced THD, as compared to PWM inverter. Simulation results confirm that the proposed controller outperforms the other existing control techniques under various set speed and torque conditions. Statistical analysis is effectively carried out to prove the effectiveness of the proposed controller. Experimental analysis is performed to validate the performance of the proposed control scheme.

     

Motor noise generation and prediction for high spinning speed hard disk drive

The acoustic level of a hard disk drive is an important specification. This is especially so for enterprise HDD which is required to operate under a high spinning speed. In order to reduce the acoustics level of a HDD, an in depth understanding behind the mechanisms whereby the noise is being generated in a HDD should be established. This paper will study the acoustics characteristics of a high speed permanent magnet brushless DC motor (PM BLDC) and investigate the physics underlying the generation of noise associated with a motor. An analysis procedure of the PM BLDC motor noise generating mechanisms is proposed. Through finite element analysis and experimental verification, the results indicate that the major noise source for the high speed PM BLDC motor is due to the presence of electromagnetic (EM) torque ripples. Furthermore, it has been observed that the noise radiated by a HDD can be amplified when its structural dynamics are close to the frequency components of the noise source. Finally, a methodology which discusses the steps involved in the prediction of motor radiated noise will be presented.     

无刷直流电机换相转矩脉动抑制的研究

针对无刷直流电机换相时产生的转矩脉动,采用自抗扰控制技术设计出一种自抗扰控制器来消除转速响应的超调,同时通过自身的扩张状态观测器检测系统的相电流脉动和自身的非线性状态反馈控制律对检测到的电流脉动误差值进行补偿抵消,以达到抑制相电流脉动的效果,从而抑制电机的转矩脉动.仿真结果表明,自抗扰控制比PI控制能更好地抑制转矩脉动,提高电机转速的稳定性和系统的可靠性.     

基于自适应干扰估测器的协作机器人关节速度波动抑制方法

针对协作机器人对高载荷自重比和高精度速度控制的需求,设计了基于双定子永磁同步电机和谐波减速器的关节模块,利用双定子结构提升了电机的转矩密度。为了提高关节速度控制精度,将摩擦等低频非线性因素、电机转矩波动和谐波减速器传递误差对关节速度波动的影响等效为关节系统的输入力矩干扰,并对其进行补偿以抑制关节速度波动。为提高干扰估测精度,提出一种基于双干扰估测器与自适应算法的方法。双定子电机性能测试结果表明,相较于单定子结构,本文的双定子电机转矩密度提升11%。关节速度控制实验表明,与单纯的比例-积分速度控制器相比,采用本文方法,关节的低速稳态波动误差的均方根减小约40%～60%,中、高速稳态波动误差的均方根减小约30%～40%,速度控制精度提升。     

一种无刷直流电机的无位置传感器控制研究

通过对电机相电压和相电流的映射,利用人工神经网络在处理非线性、不确定问题上的优势,提出一种基于FRA优化的RBF神经网络实现无刷直流电机的无位置传感器控制,估算出准确的电机换相信号。实验结果验证了本文方法的有效性。     

DSP-based control of brushless DC drives for direct-driven robotic arms

Modern permanent magnet brushless DC (BLDC) drives have excellent high-torque capabilities which make them suitable for direct-drive applications in robotic arms, but unfortunately they suffer from torque pulsations when controlled by a conventional current controller. The technique of instantaneous torque control with indirect torque sensing is aimed at reducing such torque pulsations. The AT&T DSP32, a digital signal processing chip, is used as the controller since the control algorithm requires high-speed computations. The DSP circuit has been constructed on a prototyping card and mounted in a microcomputer which serves as the program development system as well as run-time input-output controller. We present the design, implementation and experimental results of the proposed DSP-based instantaneous torque controller.     

A study on the improvement of the cam phase control performance of an electric continuous variable valve timing system using a cycloid reducer and BLDC motor

This paper discusses the control performance improvement for an electric-continuous variable valve timing (E-CVVT) system using a brushless direct current (BLDC) motor and cycloid reducer. Each component of the E-CVVT system was implemented with mathematical analysis, and the response performance of the E-CVVT system was determined based on the mathematical model of the cam shaft motion, cam profile, cycloid reducer, BLDC motor, and controller. To control the intake valve timing of the engine, a cycloid speed reducer with a high reduction ratio capable of amplifying the output torque of a small BLDC motor was implemented. The change in valve speed due to the rotation of the cam shaft was represented by the curves described by the vertical movement of the valve using the cam profile. A control performance test apparatus was constructed and the torque of the intake cam shaft was measured and applied to the analysis so that the phase of the cam shaft could be changed using the E-CVVT system. To analyze the operating characteristics of the E-CVVT system, the BLDC motors were modeled using Simulink. The E-CVVT system controls the phase angle of the intake cam shaft. When the E-CVVT system sets the target phase angle, the motor controller generates the optimal motor speed command. The intake cam phase response speed depends on the setting of each PID parameter that changes the phase of the cam shaft. Through analysis and vehicle-based experiments, we confirmed the improvement of the E-CVVT system response performance according to the change of the PID parameter.

     

矿井提升机直接转矩控制系统转矩脉动最优控制

针对矿井提升机直接转矩控制系统低速段运行时存在转矩脉动过大的问题,提出了一种矿井提升机转矩脉动最优控制方法。该方法以预测模型为基础,采用零电压矢量注入方式进行最优电压矢量的占空比调整。整个占空比计算过程以转矩脉动最小为设计指标,采用在线计算的方式实时获得最优占空比。实验结果表明,该方法在低速时可有效减小电动机转矩脉动,获得优异的转矩控制性能。