Permanent Magnet Brushless Direct Current Motors

The equivalent electrical circuit of a dc motor is shown in figure 5.2. It can be represented by a voltage source (Va) across the coil of the armature. The electrical equivalent of the armature coil can be described by an inductance (La) in series with a resistance (Ra) in series with an induced voltage (Vc) which

Brushless motors are a bit similar to normal DC motors in the way that coils and magnets are used to drive the shaft. Though the brushless motors do not have a brush on the shaft which takes care of switching the power direction in the coils, and this is why they are called brushless. Instead the brushless motors have three coils on the inner (center) of the motor, which is fixed to the mounting. On the outer side it contains a number of magnets mounted to a cylinder that is attached to the rotating shaft. So the coils are fixed which means wires can go directly to them and therefor there is no need for a brush. The reason why QuadCopters use brushless motors instead of normal DC motors is the much higher speeds and less power usage for the same speed. The brushless motors are more efficient as there is no power lost as there is in the brush-transition on the DC motors. Usually rated with a KV rating (revolutions per volt). This is not equivalent to torque, but lower KV motors are usually used for larger

The electric motors work by electricity and magnets working together. Once the electricity gets going, the magnets take over. The magnets keep the motor going because the magnets used in motors have both positive and negative magnets on both sides. Surrounding the magnetic ends, are one positive and one negative magnet. This means that at any

Economically, petroleum fuel prices have escalated in the past, which make the use of the electrical controlled vehicle a great alternative to manage the cost issues. Therefore, this research proposal focuses on Electrical Vehicle technology.

Using Field Oriented Control, current control is largely unaffected by speed of rotation of the motor[6].In the scheme of filed oriented control motor currents and voltages obtained from the motor are transformed into d-q reference frame. Measured currents from three stator phases these currents which are now in the stator reference frame are converted into two phase using Clarke transformations which are further converted into the corresponding rotor reference frame using Park transformation. The resultant current obtained is dc which is easier for the PI controllers to operate.

Brushless motors are considered to be a high performance motor that is capable of providing large amounts of torque over a vast speed

The objective of the proposed internship can be divided into the following sub-objectives – 1) develop a control strategy with variable operating switching frequency to dynamically control current ripple and reduce system losses, and 2) develop a current control strategy to improve dynamic response for the two level inverter fed PMSM drive; while taking into account the effect of different operating regions and drive design parameters. More specifically the following tasks will be accomplished for each sub-objective:

Brushless DC motors is a kind of permanent magnate synchronous motor. Permanent magnet synchronous motors are classified on the basis of the wave shape of their induce emf, i.e, sinusoidal and trapezoidal. The sinusoidal type is known as permanent magnet synchronous motor (PMSM); the trapezoidal type goes under the name of PM Brushless dc (BLDC) machine. Table (2.1) shows the difference between (PMSM) and (BLDC) motor.

However, the problems are found in these motor for variable speed operation over last decades keeping technology growth in power semiconductors, microprocessors, adjustable speed drivers control schemes and permanent-magnet brushless electric motor production have been joined to enable reliable, cost-effective solution for a wide area of adjustable speed applications.

This thesis deals with the design and analysis of control system structures for electric drives equipped with permanent magnet synchronous machines (PMSM) in automotive application.With the increasing popularity of multi-level inverters, the room for improvement of the performance of voltage source inverters has continuously been tested for various applications. The rapid development of high switching frequency power electronics in the past decade leads towards wider application of voltage source inverters in AC power generation. Therefore, this prompts the need for a modulation technique with less total harmonic distortion, fewer switching losses, and wider linear modulation range.The present thesis highlights the comparison of the conventional two-level inverter and the three-level diode clamped inverters for the application in automotive industry.

The generation of the torque in the brushed DC motors is coming directly from the DC power. The internal commutation and the magnets that are stationary (magnets can be permanent or electromagnet) supply the power to the motor to generate the torque. These motors include carbon brushes to transfer the power to the rotating shaft.

This paper investigates adjustable speed induction motor drive using 2-level and 3-level PWM.The result obtained is verified using Matlab simulation.This result compares the hamonic contect in between 2-level and 3-level by FFT analysis tool.To analyse the resulta a carrier based pwm was taken using 2- level and 3- level topology and a threephase bridge convetor with internally generated capability SPWM/SVPWM was intrduced. Carrier freqency18*60Hz, modulation index 0.9, output voltage freqency 60 Hz and ouput voltage phase 0 degre Was fixed. So corresponing to above values,the motor speed was 1800 rpm. Or 188.5 radian/sec, hence torque is 11.87Nm. A two pole squirrel cage motor was taken subjected to 400V dc source with modulation index0.9 prduces 220v rms.when motor starts, at 0.5s it reaches its steady speed 181 radian/sec or 1728 rpm. Now by discretizing the FFT tool displays the frequency spectrum of voltage and current waveforms. These signals are stored in workspace in the ASM structure with time variable generated by the Scope block. As my model is discretized, the signal saved in this structure is sampled at a fixed step and consequently satisfies the FFT tool requirements.It was observed that value of total harmonic distortion(THD) was 65.77 percent in 2-level and 35.11 percent in 3- level for SPWM invertor and 56.77 percent for SVPWM invertor.

This thesis deals with the configuration and investigation of control framework structures for electric drives furnished with changeless magnet synchronous machines (PMSM) in car application. With the expanding prominence of multi-level inverters, the opportunity to get better of the execution of voltage source inverters has persistently been tried for different applications. The fast improvement of high exchanging recurrence power gadgets in the previous decade leads towards more extensive use of voltage source inverters in AC power era. In this way, this prompts the requirement for a regulation method with less aggregate symphonious bending, less exchanging misfortunes, and more extensive direct balance range. The present theory highlights the examination of the customary two-level inverter and the three-level diode cinched inverters for the application in car industry.

Abstract—This paper proposes direct torque control of induction motor simulation using conventional method and space vector pulse width modulation technique for ripple reduction. Direct Torque Control is a control technique used in AC drive systems to obtain high performance torque control and thereby controlling the speed of induction motor. The principle is based on simultaneous decoupling of stator flux and electromagnetic torque of AC drive system. DTC drives use hysteresis comparators and they suffer from high torque ripple and variable switching frequency problem. The proposed SVM based DTC reduces torque ripples. The basis of the SVM-DTC methodology is the calculation of the required voltage space vector to compensate the flux and torque errors and its generation using the SVM at each sample period. The performance of this method is demonstrated by simulation using MATLAB/Simulink software. Simulation results presented in this paper show the torque, flux linkage and stator current ripple decreases with the proposed SVM-DTC algorithm.

The design and build of simulation has two parts, part one is simulation of LED indicator for motor speed recognize and part 2 is simulation of V/F speed control of Linear induction motor. Firstly, design