Permanent Magnet Brushed DC Motor Research Articles

Effect Comparison of Zigzag Skew PM Pole and Straight Skew Slot for Vibration Mitigation of PM Brush DC Motors

The electromagnetic vibration of permanent magnet brush dc (PMBDC) motors has its distinct feature, where only slot-frequency related components exist. Skew slot technique is naturally recalled to mitigate the slot-frequency vibration. Unfortunately, the straight skew slot normally used is not as effective as the mitigation of tooth harmonic electromotive force (EMF) or cogging torque. First, in this paper, the principle of vibration mitigation by straight skew is discussed and compared with mitigation of tooth harmonic EMF and cogging torque. The reason for poor effect of straight skew slot is illustrated by a specifically-designed experiment and finite-element method (FEM) simulation. In order to solve this problem, the zigzag skew PM pole technique is proposed for PMBDC motors for the first time, which overcomes the disadvantage of straight skew slot. The pulsating radial force and bending moment, two main causes of electromagnetic vibration, are derived and analyzed analytically and by the three-dimensional FEM for zigzag skew PM poles. At last, the experiments on two PMBDC motors, one with straight skew slots and the other with zigzag skew PM poles, are conducted to verify the effectiveness of the zigzag pole technique.

A PM Pole With Axial Varied Width for Vibration Mitigation in PM Brush DC Motors

This paper presents a PM pole with varied width in the axial direction for vibration mitigation in permanent magnet brush dc motors, which is proposed to decrease the deformation caused by radial pulsating force and bending moment together. First, the air gap flux density distribution and radial force density distribution are derived in detail. After two types of vibration modes and their reasons as pulsating force and bending moment are analyzed, the difficulty in vibration mitigation is pointed out. By investigating the change rule of the pulsating force and bending moment with PM pole width, a type of PM pole with varied width in the axial direction is proposed. Its principle of deformation reduction is presented, and the optimized pole shape is derived. A three-dimensional finite-element method is used to calculate the magnetic field, Maxwell force, modal analysis, and deformation of motors. In order to verify the effectiveness of the proposed method, the vibration of the proposed motor is compared with the other three types of traditional motors, including skewing slot or skewing pole. Finally, experimental results of two types of motors are compared to validate the proposed technique.

An Effective Method With Copper Ring for Vibration Reduction in Permanent Magnet Brush DC Motors

This paper presents a new method by sticking a copper ring on the permanent magnet pole of the permanent magnet brush dc (PMBDC) motor to reduce the electromagnetic vibration. First, the air-gap flux density distribution and radial force density distribution are derived and the principle of the electromagnetic vibration reducing technique by the copper ring is analyzed in detail. Then, finite-element method is used to calculate the Maxwell force and the vibration spectrum of a 2-pole 24-slot PMBDC motor and a modified motor. Finally, experimental results are given to validate the proposed technique, by testing the vibration spectrum of the two prototype PMBDC motors. It is shown that the acceleration of the motor with copper ring can reduce the vibration effectively compared with the origin motor, and the reduced ratio can be up to 40%.

Analysis and Experimental Verification of Electromagnetic Vibration Mode of PM Brush DC Motors

The vibration mode of electric machines is an important characteristic of vibration, which is useful for finding the vibration sources with different frequencies, but has always been neglected before. In this paper, the vibration characteristics, especially the vibration mode, of permanent magnet (PM) brush DC motors are studied. First, the air gap flux density distribution and radial force density distribution are derived in detail and compared with the results of the finite-element method. Then, two types of vibration modes, called pulsating and bending modes, and their reasons as pulsating force and bending moment are analyzed and elaborated, which have not been analyzed and verified sufficiently before. In addition, the relationships between these two vibrations and pole width, pole number, and slot number are analyzed. The main modal shapes and their frequencies are acquired from the modal test. To confirm the analysis and theory, the multiprobe mode-included test method of vibration acceleration is proposed and emphasized to obtain the vibration mode information of motors, and the experimental results on a PM brush DC motor match well with the simulation results.

Analysis of Chaos and Bifurcation Due to Slotting Effect and Commutation in a Current Discontinuous Permanent Magnet Brushed DC Motor Drive

The aim of this paper is to study the dynamics of a permanent magnet direct current (PMDC) brushed motor while two crucial space-domain effects, namely, slotting effect and commutation phenomenon are taken into account. Semi-analytical dynamic time-domain PMDC brushed motor model inclusive of these space-domain effects is used to analyze and investigate the dynamics. Pulse width modulation operated discontinuous current PMDC brushed motor drive with steady duty cycle is employed to acquire the bifurcation patterns. The chaotic nature due to slotting effect and commutation is identified from the bifurcation patterns and reported. It also has to be admired that such nonlinear dynamical behavior with the same set of parameters at similar operating condition has not been observed when a conventional PMDC brushed motor dynamic model is considered. These space-domain effects, namely, slotting effect and commutation also have a prominent impact to make some time-domain states of a PMDC brushed motor drive chaotic. The role of slotting effect and commutation phenomenon to analyze the chaos over time-domain state variables of the PMDC brushed motor drive is investigated and validated experimentally in this paper.

Precision concurrent speed and position tracking of brushed dc motors using nonlinear time-frequency control

Brushed DC motors are essential components in a wide range of applications in which their unique benefits are explored. However, their being inherently nonlinear and sensitive to system based uncertainties such as load variation and process noise has made improving the precision control of brushed DC motors a challenging task. To mitigate such negative effects that invariably undermine motor stability and controllability, a novel wavelet-based nonlinear time-frequency control scheme viable for the concurrent speed and position tracking of brushed DC motors is presented. The control approach has its basis in discrete wavelet transformation and adaptive control. Considering system response in the wavelet domain allows the true dynamics of the system as delineated by both the time and frequency information of the response to be faithfully resolved without being distorted or misinterpreted. By employing adaptive theory, the undesirable features typical of nonlinear brushed DC motor systems such as being highly unstable and energy inefficient are also properly addressed. The validity of the controller design are demonstrated by evaluating its performance and the power requirement against PID control and fuzzy logic control in mitigating the speed, position, and armature voltage responses of a permanent magnet brushed DC motor under severe system uncertainties. The proposed nonlinear controller is shown to be accurate, robust, energy efficient, low in power requirement, and easy to switch between speed and position control.

Development and modification of permanent magnet brushed DC motor for hybrid photovoltaic-operated solar systems

A modified brushed permanent magnet DC (PMDC) motor has been developed and fabricated for a photovoltaic (PV)-operated solar systems. The conventional PMDC motor has been plagued with constraints, the most critical being ingestion of vapours of working fluid inside the rotor and stator, damaging the insulation of windings and forming a thin film of moisture between commutator and brushes. This flaw results into a very low mean time between failures of the motor. In the past, many attempts have been made where-in variety of seals to isolate the working fluid vapours from inner parts of motor have been tried out, but to no avail. Even Brushless DC motors have been designed in the past but their exorbitant cost makes the entire arrangement not viable economically. The modification attempted in this article overcomes the problem of working fluid ingestion inside the motor. It is found that mass flow rate of working fluid obtained at maximum peak sunshine hours is 17.5 l/min at 3030 rpm of motor driven by a PV module of 40 W at 16.20 V. This low-cost modified PMDC motor has been robust with high mean time between failures as no breakdown observed during 18 months of operation.

Intelligent control of DC motor driven electromechanical fin actuator

In this paper modeling, simulation and control of an electromechanical actuator (EMA) system for aerofin control (AFC) with permanent magnet brush DC motor driven by a constant current driver are investigated. Nonlinear model of the EMA-AFC system has been developed and experimentally verified in actuator test bench. Model has been used as the starting point for PID position controller synthesis. To improve performances of the system, computational intelligence has been applied. Genetic PID optimization, genetic algorithm (GA) optimized fuzzy supervisory PID control and finally GA optimized nonlinear PID algorithm modification are proposed. Improved transient response and system behavior have also been experimentally validated.

Modeling, simulation, and control of an electromechanical aerofin control system with a PWM-controlled DC motor

A nonlinear model of an electromechanical actuator (EMA) system for aerofin control is presented. The EMA is realized with a permanent magnet brush DC motor controlled by a constant current driver. In this paper we introduced a simulation model that includes nonlinearities of the motor driver. A PID position controller was designed using the simulation model, although it was impossible to develop a linear model. The simulation results have been of the great importance for understanding the system behavior and successful control system implementation. The proposed control system has experimentally been validated on a test bench. The EMA-AFC test bench is designed to provide real operating conditions.

Backstepping boundary control of flexible-link electrically driven gantry robots

Gantry robots are used for precision manufacturing and material handling in the electronics, nuclear, and automotive industries. Light, flexible links require less power, but may vibrate excessively. An implementable boundary controller is developed to damp out undesirable vibrations in a flexible-link gantry robot driven by a brushed DC motor. Hamilton's principle produces the governing equations of motion and boundary conditions for the flexible link. The electrical subsystem dynamics for a permanent magnet brushed DC motor couple with the link dynamics to form a hybrid system of partial and ordinary differential equations. A boundary voltage control law is developed based on Lyapunov theory for distributed parameter systems. Through an embedded desired-current control law, the integrator backstepping controller generates the desired control force on the mechanical subsystem. A velocity observer estimates the gantry velocity, eliminating one feedback sensor. Modal analysis and Galerkin's method generate the closed-loop modal dynamics. Numerical simulations demonstrate the improved vibration damping characteristics provided by the backstepping boundary control law. Experimental results confirm the theoretical predictions, showing the high performance of backstepping boundary control.

Integrator backstepping techniques for the tracking control of permanent magnet brush DC motors

An integrator backstepping technique is introduced for the design of high-performance motor controllers. The approach is applied to the design of embedded computed torque and output feedback controllers for permanent magnet brush DC (BDC) motors. The proposed controllers are simulated and experimentally verified on a user-developed digital signal processor (DSP) based data acquisition and control (DAC) system. Although the BDC motor is well researched, the results motivate extensions of the proposed techniques to the development of similar controllers for more complex electromechanical systems, such as separately excited DC, permanent magnet stepper, brushless DC, switched reluctance, and AC induction servo motors.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>