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Abstract
This paper details current state of the art with respect to digital motor commutation techniques illustrates the distinct advantages and disadvantages of each technique and goes on to propose a novel current control technique aimed at increasing efficiency at high speed part load conditions.
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... It is simple in implementation, but it has variable switching frequency and leads to high frequency ripple. To improve the performance of current regulation, some fixed-frequency PWM methods have been proposed [5]. One-cycle control (OCC) technique is a nonlinear control method with a simple topology that operates in constant frequency and does not require any complex power processing circuits [6]. ...
One-Cycle Control (OCC), as a unified constant-frequency integration control strategy for current control of brushless dc (BLDC) motor drive is presented in this paper. Employing the one-cycle control strategy reduces high frequency torque ripple of conventional hysteresis current controllers that leads to lower acoustic noise and vibration of the drive. Moreover, to enhance reliability and reduce total cost of the drive, an improved low-cost rotor position estimation strategy is implemented. It is based on detection of the true back-EMF zero-crossing points that can be directly extracted by detection of voltage between phase terminal and midpoint of dc link without motor neutral point voltage. Total operations of OCC strategy and sensorless method are realized by a low-cost general-purpose AVR microcontroller (Atmega8) that leads to a low-cost, high performance sensorless BLDC motor drive. Computer simulations using Matlab simulator, have been presented to show characteristics of this solution. Experimental results with a 230 W, 14 poles BLDC motor, show improved behavior of developed sensorless BLDC drive in both steady-state, and transient situations.
... It is simple in implementation, but it has variable switching frequency and leads to high frequency ripple. To improve the performance of current regulation, some fixed-frequency PWM methods have been proposed [5]. One-cycle control (OCC) technique is a nonlinear control method with a simple topology that operates in constant frequency and does not require any complex power processing circuits [6]. ...
Traditional BLDC motor drives use voltage source inverters (VSI) that utilize PWM and hysteresis hard switching methods. It leads to generate switching losses and need to use of large heat sinks. VSIs are costly because of low reliability and need to large DC link capacitor. Moreover, common control methods such as hysteresis current control can create variable range of high frequency noises. This paper overcomes the problems of VSIs and reduces the volume and cost, by using current source inverter (CSI) which replaces an inductor instead of DC link capacitors. Also, to solve the problems of hysteresis control method, one-cycle control (OCC) technique has been used for soft switching of the inverter. Moreover, to reduce the difficulties and cost of installing electromechanical sensors in BLDC motors an appropriate method for rotor position estimation has been presented. Simulation results in Matlab/Simulink verify the effectiveness of OCC-based control of CSI-BLDC motor drive comparing to hysteresis-based VSI-BLDC motor drive.
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.
This paper provides a technical review of position and speed sensorless methods for controlling Brushless Direct Current (BLDC) motor drives, including the background analysis using sensors, limitations and advances. The performance and reliability of BLDC motor drivers have been improved because the conventional control and sensing techniques have been improved through sensorless technology. Then, in this paper sensorless advances are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks, including the analysis of practical implementation issues and applications. The study includes a deep overview of state-of-the-art back-EMF sensing methods, which includes Terminal Voltage Sensing, Third Harmonic Voltage Integration, Terminal Current Sensing, Back-EMF Integration and PWM strategies. Also, the most relevant techniques based on estimation and models are briefly analysed, such as Sliding-mode Observer, Extended Kalman Filter, Model Reference Adaptive System, Adaptive observers (Full-order and Pseudoreduced-order) and Artificial Neural Networks.
Control methods for the pulsation of torque reduction for the
surface-mounted permanent magnet motors are discussed. The pulsation
torque is a consequence of the non-sinusoidal flux distribution and due
to interaction of the rotor's permanent magnets with the changing stator
reluctance. The proposed control method is an estimator based. To ensure
parameter convergence the Lyapunov direct method is used in the
estimator design for the flux Fourier coefficients. A novel nonlinear
torque controller based on the flux/torque estimate is introduced to
reduce the influence of the flux harmonics. The influence of the cogging
torque is considerably reduced at lower motor speed using the internal
model principle and adaptive feedforward compensation technique. An
overall control scheme and experimental results are also presented
With ever-increasing concerns on our environment, there is a fast growing interest in electric vehicles (EVs) and hybrid EVs (HEVs) from automakers, governments, and customers. As electric drives are the core of both EVs and HEVs, it is a pressing need for researchers to develop advanced electric-drive systems. In this paper, an overview of permanent-magnet (PM) brushless (BL) drives for EVs and HEVs is presented, with emphasis on machine topologies, drive operations, and control strategies. Then, three major research directions of the PM BL drive systems are elaborated, namely, the magnetic-geared outer-rotor PM BL drive system, the PM BL integrated starter-generator system, and the PM BL electric variable-transmission system.
In order to save resources and prevent global warming, there has been a pressing need in recent years to reduce the volume of CO2 emissions, and to improve the fuel consumption of automobiles. Due to environmental concerns, the recent regulation on automobile fuel economy has been strengthened. The market demand for efficient vehicles is growing and automakers to improve engine fuel efficiency in the industry have been paying a lot of effort. Under these circumstances, the mechanical parts in the automobile industry are being replaced by electronic methods. In this paper, authors introduce two methods. First method is water pump. Especially, to improve vehicle engine efficiency, power transmission and around the field of devices according to driving conditions need to be properly cooled. Conventional mechanical water pump is directly connected by the engine belt. For this reason, regardless of coolant circulation, the conventional mechanical water pump is always operated. However, the electric water pump can be operated only when needed through the proper motor speed control. The way which the mechanical water pump is replaced by electric water pump could reduce energy consumption. Second method is VVA (Variable Valve Actuation) technology. To improve the fuel efficiency, it is necessary to reduce losses or to improve combustion efficiency of the engine. VVA technology enhances the engine's intake air flow, reduce pumping losses and mechanical friction losses. And also, VVA technology is the engine's low speed and high speed operation to implement each of appropriate valve lift. It improves the performance of engine in the entire operating range. This paper presents a design procedure of drive for water pump and VVA system and shows the validity of the result by experimental result with prototype.
There has been an ever-increasing demand to increase the switching frequency, power density, efficiency and dynamic performance of switch-mode power converter, the development of soft-switching technology has taken an accelerated pace. This paper provides a review on the development of soft-switching power converters for electric vehicle (EV) propulsion and recent research trends will also be discussed, with emphasis on soft-switching convert-ers for dc motor drives, soft-switching inverters for ac motor drives and soft-switching converters for switched reluctance motor (SRM) drives.
This paper presents a software-defined digital controller for the permanent magnet brushless dc motor using field-oriented control (FOC). The proposed controller that improves the system performance in low torque ripple, and high efficiency is introduced and discussed in detail. The proposed FOC controller is implemented with a MC73110 motor control chip for experimental verification under 400 W and 9,160 rpm. The experimental motor waveforms and torque ripples with different commutation methods are investigated.
Working with the subject of sensorless motor control requires an understanding of several topical areas; this report presents an understanding that was gained during this research work. The fundamentals of electric motors (particularly brushless motors) are developed from first principles and the basic models are discussed. The theory of sinusoidal synchronous motors is reviewed (phasor analysis of the single phase equivalent circuit). The concept of a complex space vector is introduced and developed using a working knowledge of the sinusoidal synchronous motor. This leads to the presentation of the space vector model of the permanent magnet synchronous motor, in both the stationary and rotor reference frames. An overview of the operation of three-phase voltage source inverters is given, followed by an explanation of space vector modulation and its relationship to regular sinusoidal pulse width modulation. Torque control of the permanent magnet synchronous machine is reviewed in several reference frames and then rotor-flux-field-oriented-control is explained. Finally, some schemes for sensorless operation are discussed. ICE Corporation Master of Science Masters Department of Electrical and Computer Engineering James E. DeVault
The application of direct torque control (DTC) to brushless AC drives (BLAC) has been investigated extensively. This work describes its application to brushless DC drives (BLDC), and highlights the essential differences in its implementation, in relation to the 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, instantaneous torque control results in reduced torque ripple and a faster torque response.
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
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.
Permanent magnet machines with trapezoidal back EMF waveform have
been the subject of several papers in the past. The simplicity in
control and the absence of an absolute position sensor makes this type
of motor very attractive. Idealized analysis of such a machine is simple
and will result in trapezoidal or square wave back EMF waveforms
depending on the assumptions made. In the case of an idealized
quasi-square wave current excitation, a ripple-free torque will be
obtained. The actual back EMF waveform of these machines depends on the
flux density and the conductor distributions. This in turn is a function
of the magnet magnetization and the stator tooth and slot structure. In
applications where a fairly smooth torque is needed, these machines are
made with either the stator slots or the rotor magnets skewed by one
slot. This paper deals with the analysis of the back EMF waveform and of
the torque ripple waveform of such a machine when the stator slots or
rotor magnets are skewed by one slot. The analysis takes into
consideration the actual stator conductor distribution and the effect of
magnet magnetization on the back EMF waveform. An empirical formula is
developed for the magnet flux density distribution which could be used
for various magnetization conditions of the magnet. Experimental results
are included to confirm the analytical results
Brushless DC (BLDC) Motor Fundamentals [Microchip Technology Inc. AN885] .
Padmaraja Yedamale
A Comparison Study of the Commutation Methods for the Three-phase Permenent Magnet Brushless Motor.
Tom Lemley
Shiyoung Lee
Implementing field oriented control of a brushless DC motor
Cypress Semiconductor
Meenakshi Sundaram
Development of BLDC motor drive for automotive applications," in ESARS electrical systems for aircraft, railway and ship propulsion
Bon-Gwan
Jin-Hong Gu
Jun-Hyuk Kim
Choi
Field Orientated Control of 3-phase AC-motors
Texas Instruments
A new approach for minimum-torqueripple maximum-efficiency control of bldc motor
Man Hyung Han Woong Park
Fumio Lee
Harashima
Development of bldc motor drive for automotive applications