Method For Brushless DC Motors Research Articles

Constant rate magnetic weakening control method of brushless DC motor based on current advance angle method

Constant rate magnetic weakening control method of brushless DC motor based on current advance angle method

A constant rate magnetic weakening control method of brushless DC motor based on current advance angle method

A constant rate magnetic weakening control method of brushless DC motor based on current advance angle method

Low speed sensorless control method of brushless DC motor based on pulse high frequency voltage injection

A low speed sensorless position control method for brushless DC motor based on pulse pulse high frequency voltage injection is proposed according to the characteristic that the brushless DC motor (BLDCM) which is produced at present makes the counter electromotive force waveform show sinusoidal waveform in view of the problem that it is difficult to accurately obtain the rotor position and speed of the brushless DC motor at zero and low speed. Its principle is to inject high frequency sinusoidal voltage signal on the estimated direct axis of the synchronous rotating coordinate system so that the motor can generate saturated salient effect, obtain the estimation error containing the rotor position information, and by detecting the output current of PI regulator of quadrature axis current loop, and then estimate the initial position of the rotor and judges the magnetic pole, realize the determination of the actual rotor position, finally, realize the non-position static low speed control of BLDCM by adding current and speed rings. According to the simulation test, it shows that this method can detect the position and speed of the motor rotor well at both zero speed and low speed.

Parameter Tuning of Brushless DC Motor for Improving Control Effect with Worm Algorithm

Aiming at the problem of low control precision and small applicable scope caused by adjusting control parameters in Ziegler-Nichols (ZN) method, a parameter tuning method based on Worm algorithm (WOA) is proposed for Brushless DC motor. Firstly, the model of speed control is established by proportional integral method for Brushless DC motor with two - phase conduction and three - phase full bridge drive. Then the fitness function of the controller is constructed by the Integral Absolute Error (IAE). Finally, the early optimization process, the later movement rule and the peak extraction rule are determined for WOA, and the controller parameter tuning process is designed. Simulation results under constant and sinusoidal conditions show the effectiveness of the proposed method. WOA was compared with ZN, genetic algorithm (GA), differential evolution algorithm (DE) and particle swarm optimization algorithm (PSO) in the experiment. The experimental results show that the control effect (CE) of WOA under uniform speed has been improved by 2.56% on average, and has been improved by 16.93% on average under sinusoidal speed. Compared with previous methods, this method can be used for parameter adjustment of complex control with higher control precision.

A New Approach of Minimizing Commutation Torque Ripple for BLDCM

The properties of brushless DC motor (BLDCM) are similar to the fractional, slot-concentrated winding of permanent-magnet synchronous machines, and they fit well for electric vehicle application. However, BLDCM still suffers from the high commutation torque ripple in the case of the traditional square-wave current control (SWC) method, where the current vector rotates asynchronously with back-EMF. A current optimizing control (COC) method for BLDCM is proposed in the paper to minimize the commutation torque ripple. The trajectories of the three phase currents are planned by the given torque and the optimized result of the copper loss and motor torque equations. The properties of COC are analyzed and compared with that of SWC in the stationary reference frame. The results show that the way of making the current vector rotate synchronously with back-EMF (back-Electromotive Force) can minimize the modulus and velocity of the current vector in the commutation region, and reduce the torque ripple. Experimental tests obtained from an 82 W BLDCM are done to confirm the theoretical findings.

Novel Phase Advance Method of a BLDC Motor for Wide Range Speed Operations

his paper proposed a novel phase advance method for brushless DC motors (BLDCMs) to extend the speed operating range, and obtain the maximum torque in the high speed operation region. The angle of the phase currents should be advanced about the back-EMF to increase the speed operating region and obtain maximum torque. Many advance methods have been studied for BLDCMspeed expansion. The conventional method could widen the speed range, but also increase the torque ripple. To resolve the issues with conventional methods, the proposed method broadens the conductive angle of the phase current including advancing the phase current angle to the back-EMF (Electro-Magnetic Force). The broad conductive angle is derived by analyzing the phase current and back-EMF. The usefulness of the proposed method is verified through mathematical analysis, computer simulation and experimental results.

A novel direct torque control method for brushless DC motors based on duty ratio control

Conventional direct torque control (DTC) suffers from large torque ripple and nonconstant switching frequency, which are caused by the hysteresis band amplitude and the motor speed. Many methods have been proposed to tackle these problems. However, these methods are usually complicated and parameter dependent. A novel DTC method for brushless DC motors based on duty ratio control is proposed to reduce torque ripple and maintain a constant switching frequency. During each switching period, an active voltage vector and a zero voltage vector are applied. A simple and effective method implemented to calculate the duty ratio relies only on the torque error, reducing the parameter dependence. The proposed method has the advantages of conventional DTC and effectively reduces torque ripple, which improves the performance of conventional DTC. Simulation and experimental results are given to confirm the method’s validity.

Efficiency Comparison of Trapezoidal and Sinusoidal Method for Brushless DC Motor Drive

This paper compares overall efficiency of trapezoidal BLDC motor which is excited by trapezoidal drive and sinusoidal drive. The different characteristics and performance of trapezoidal Brushless DC (BLDC) motor is formed by driving methods. Sinusoidal drive that excites trapezoidal BLDC motor generates greater maximum torque than trapezoidal drive. However, with regard to high frequency loss caused by a pulse width modulation (PWM) carrier and switching loss, the trapezoidal drive has potential to achieve higher efficiency than the sinusoidal drive. Thus, these two drive methods excite trapezoidal BLDC motor are compared to study the efficiency performance. The motors drives are simulated by using MATLAB and their efficiency are measured. The results show that the trapezoidal BLDC motor with trapezoidal drive has higher efficiency compared to trapezoidal BLDC motor with sinusoidal drive.

Research on Speed Control Problem of Industrial Sewing Machine System

This paper presents a new method of braking control related to the brushless DC Motor control industrial sewing machine system by analyzing the braking method of brushless DC Motor and the characteristics of control method concerning industrial sewing machines system. With the RENESAS SH7125 MCU as the core controlling, this paper analyzes from the both aspects of speed regulation and braking control, adopts oscillating circuit frequency input method for frequency control, reversing locking brake by detecting needle position signal. Practice proves that the method has achieved good effect, met the control requirements of the industrial sewing machine system.

The Sliding Mode Variable Structure Control Method for Brushless DC Motors

The sliding mode variable structure control method for brushless DC motors with uncertain external disturbances and unknown loads is studied. A neural sliding mode control scheme is proposed for reducing chattering of sliding mode control. A global sliding mode manifold is designed in this approach, which guarantees that the system states can be on the sliding mode manifold at initial time and the system robustness is increased. A radial basis function neural network (RBFNN) is applied to learn the maximum of unknown loads and external disturbances. Based on the neural networks, the switching control parameters of sliding mode control can be adaptively adjusted with uncertain external disturbances and unknown loads. Therefore, the chattering of the sliding mode controller is reduced. Simulation results proved that this control scheme is valid.

Simple Lead Angle Adjustment Method for Brushless DC Motors

This paper presents a simple lead angle adjustment method for brushless DC motors. The proposed method is based on the motor current dynamics analysis during the current commutation interval. With the proposed scheme, the phase current and phase back-EMF voltage are in phase and the BLDC motor and drive system have a high efficiency induced by the reduced copper and conduction losses. Experimental results are shown to validate the proposed method.

BLDC 모터로 구동되는 오일 펌프 제어 시스템의 설계 및 구현

In this paper, we address the problem of designing and implementing an oil pump control system driven by a brushless DC (BLDC) motor. The proposed oil pump plays the role of providing fuel to the engine clutch and transmission of hybrid vehicles. Main consideration is given to enhancing response feature and accuracy of the oil pump by simplifying the controller that is driven by a BLDC motor under PWM voltage control, which is a standard control method for BLDC motors. The proposed control scheme also helps to increase efficiency and reliability of the oil pump system. To validate the performance of the proposed system, we conduct experiments on BLDC motor speed control and oil pump operations.

A Novel Control Method for BLDCM Based on Phase Back-EMF Observation

The main purpose of this study is to propose a novel back-EMF observer. It can drive a permanent magnet Brushless DC Motor (BLDCM) smoothly from slow to high speed without position or speed sensors. In the method, a phase back-EMF observer, which could estimate phase back-EMFs in real time and only relies on DC voltage and phase currents of motor without an additional circuit or complicated operation process,had been established with phase back-EMF as a disturbance signal. This observer simplifies the structure of traditional back- EMF observers and only has one inertia element, hence the response time and robustness of the system could be improved. This study also detailedly provides a method for speed and position detection, which has high performance in low speed range. The validity of the proposed method is verified through simulation and experimental results.

Control Method of Brushless DC Motor Applied in Human Skeleton Booster

This paper carries research on the method of smooth method of Brushless DC Motor. Brushless DC motor applied in human skeleton booster is required to switch frequently among four-quadrant operation states of forward rotation, backward rotation, electro motion and braking control. Basically, this switch is expected to be soft. That means it is unexpected that motor comes about the phenomenon of impact of great force, speed mutation and so on. According to the requirement, the paper presents the design of driving circuit of brushless DC motor and put forward a corresponding control method. In the end, the paper proved the correct of this method by using simulation and experimental data.

A novel position-sensorless control method for brushless DC motors

This paper presents the design and implementation of a high performance position-sensorless control scheme for the extensively used brushless DC (BLDC) motors. In the proposed method, with proper PWM strategy, instead of detecting the zero-crossing point (ZCP) of the nonexcited motor back electromagnetic force (EMF) or the average motor terminal to neutral voltage, the true zero-crossing points of back EMF are extracted directly from the difference of the specific average line-to-line voltages with simple RC circuits and comparators. In contrast to conventional methods, the neutral voltage is not needed and the diode freewheeling currents in the nonconducted phase are eliminated completely; therefore, the commutation signals are more accurate and insensitive to the common-mode noise. Moreover, 100% pulse-width-modulation (PWM) duty ratio control of BLDC motors is provided with the presented method. As a result, the proposed method makes it possible to achieve good motor performance over a wide speed range and to simplify the starting procedure. The detailed circuit model is analyzed and some experimental results obtained from a sensorless prototype are shown to verify the analysis and confirm the validity of the proposed method.

A novel sensorless control method for brushless DC motor

The authors present the theory and implementation of a novel sensorless control method for the interior permanent magnet (IPM) brushless DC motor (BLDCM). The proposed new sensorless technique can accurately detect the zero-cross point (ZCP) of back electromotive force (BEMF), which is based on a comparison of the terminal voltage of the unconducting phase during the first and second part of a pulse width modulation (PWM) cycle. Compared with the conventional BEMF sensorless approach, the proposed new sensorless method solves the problem of the sensorless BLDCM drives at very low speeds. Experimental results confirm the validity of the new method.

Simple position sensorless starting method for brushless DC motor

Position sensorless methods for brushless DC motors based on back-EMF zero crossing suffer from a starting problem since there is no back-EMF at standstill. A simple method by which the motor is started from standstill up to a speed wherein sensorless methods will be able to detect the correct commutation instants is proposed. The proposed method relies on a difference of line voltages measured at the terminals of the motor. It is shown that this difference of line voltages provides an amplified version of an appropriate back-EMF at its zero crossings. It is further demonstrated that this information can be used to trigger devices so as to develop an accelerating torque from zero speed. This method is simple to implement and it can reliably start the motor even with load. The effectiveness of the proposed method is demonstrated through simulation and hardware results.

Position sensorless driving of BLDCM using neural networks

AbstractA sensorless driving method of brushless DC motors (BLDCM) using neural networks has been studied in this paper. Considering the nonlinear characteristics and the parameter error of the modeling, neural networks are introduced to estimate the electromotive force (EMF). The results of simulation and experiment using offline trained neural networks show that the proposed method is useful. In addition, the robustness about the parameters is discussed. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 64–71, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20240

Position Sensorless Driving of BLDCM Using Neural Networks

A sensorless driving method of brushless DC Motors (BLDCM) using neural network has been studied in this paper. Considering the nonlinear characteristics and the parameter error of the modeling, neural networks are introduced to estimate the electromotive force (EMF). The results of simulation and experiment using offline trained neural networks show the proposed method is useful. In addition, the robustness about the parameters is discussed.

Simplified simulation methods for polyphase brushless DC motors

This paper presents a simulation method for brushless DC motors. The purpose of this method is to provide a solution to the initial design process, where the simulation speed is important due to the numerous variables that have to be considered. The method requires a reduced number of parameters in order to simplify it and to facilitate the design process. It is applicable to polyphase motors regardless of its connection or phase number. The simulation method can simulate the phase current control system or a DC bus current feedback system. The later control system is widely used in low-cost brushless DC motors. The simulation method is based upon the average value modelling of the inverter leg, at the PWM scale, in different modulation conditions, modelling almost all the inverter structures with transistors as active elements. The experimental results from a seven-phase brushless DC motor with one uncontrolled phase validate the modelling method. The comparison of the average torque, the current, voltage and torque waveforms in several operating conditions shows that the simulation method can predict the comportment of a brushless DC motor without an excessive computational burden, so it can be readily used as a design tool for this kind of motor.