Minimization Of Torque Ripples Using Pwm Technique For Minimizing The Torque Ripple

TM4, the industrial partner, is a leading manufacturer and supplier of traction motors and drives for electric vehicle industry in Canada. As a drive manufacturer, they always aim to provide solution which is energy efficient with small footprint. In order to achieve this, they always look for alternative software and hardware solutions. Software modifications, which may improve the system performance in comparison to their existing drive control strategy without increasing the size of the system, are always sought after for continuous improvement of their system. In this regards, the internship is relevant to them for exploring alternative control strategies.

Abstract--Multilevel inverter finds its application in high voltage high power converters. Various topologies of multilevel inverter provides several advantages such as high efficiency, low voltage stress, low EMI, better waveform and improved THD. This paper presents the development of Xilinx FPGA as a control circuit for generation of the pulse width modulation (PWM) signal for the single-phase cascaded H-bridge multilevel inverter and modified H-bridge PWM multilevel inverter. The XILINX FPGA based modified multilevel PWM inverter was implemented by adding bi-directional switches to the conventional bridge topology. Xilinx System Generator/MATLAB software has been used for simulation and verification of the proposed circuit before implementation.

The impact of the proposed sequences has been simulated for 0.4 modulation index with a 0.5 lagging power factor load (power factor angle 60°). The simulation setup consists of the following software: 1) MATLAB/Simulink – used to implement the modulation strategies and switching sequences, and 2) PSIM – used to simulate the T-NPC inverter running with an R-L load and to provide conduction and switching losses of each switch. The inverter switching pulses were generated within Simulink and were fed to PSIM through sim-coupler module which provides a link between PSIM and simulink for the purpose of co-simulation [29].

In this chapter, an overview of the state of the art system of an induction motor is carried out. It looks at various induction motor control methodologies utilizing current and voltage control to control the flux and the torque of the dynamic system. Highlight of the current and future challenges of induction motor drives are presented. To do that, a general principle of induction motor drives is discussed first follow by phase controlled of induction motor drives, frequency controlled of induction motor, and vector controlled of induction motor.

So that the voltage and current is of poor qualities and the switching frequency causes more amount of switching losses. Those drawbacks are rectified using three phase neutral point clamped multilevel inverter. The voltage and current quality are better and the switching losses are reduced when compared to the conventional technique. Also the THD is found to be better.

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 permanent magnet DC motors are being manufactured and used increasingly in everything from home appliances to automobiles due to their inherent advantages. The merits of these motors could be enhanced further according to another design approach method which alters the typically used winding parts for low to medium power range motors. This paper deals with the high power brushless DC motor used for traction in a 48 V golf cart system.

Pulse width modulation or PWM is the basic analysis for control modulation in the power electronics. PWM is a powerful and commonly used technique for controlling the analog circuits or power to electrical devices and made practical by a processor’s digital output such as the modern electronic power switches. Theoretically, the zero rise time and fall time of an ideal PWM, waveform represents a way of driving latest semiconductor power devices. Except for the resonant converters, majority of power electronics circuits are controlled by PWM signals of several forms.

Abstract: This paper investigates the dynamic performance of three phase induction motor by vector control method. The vector control algorithm is calculated on Motorola DSP56F80X. The block diagram is shown in figure which describes the structure of implement vector control algorithm. The result obtained is verified using matlab simulation. Initially speed reference is set at120 radian/s and torque taken as 0 nm. Then motor is run, speed, torque and current wave form is taken. Now speed reference changes to 160 radian/s and torque changes to 200nm and correspondence wave form is shown. I observed that it run smoothly over the full speed range, generate full torque at zero speed, and have high dynamic performance including fast acceleration and deceleration. It was originally developed for high-performance motor application for industrial drives. However, it is becoming increasingly attractive for lower performance applications as well due to FOC 's motor size, cost and power consumption reduction superiority. .. In vector control method machine is control in a synchronously rotating frame where as in sinusoidal machine variables appears as D.C. quantities. In steady state current resolved in to two control inputs I. e. direct axis and quadrature axis component

Switching power converters offer an easy way to regulate both the frequency and magnitude of the voltage and current applied to a motor shown in fig(1). As a result much higher efficiency and performance can be achieved by these motor drives with less generated noises[3].

The modulation methods used in multilevel inverters can be classified according to the switching frequency was discussed in Rodriguez et al (2002), Celanovic and Boroyevic (2001) and Rodriguez et al (2001). Modulation techniques that work with high switching frequencies have many commutations for the power semiconductors in a cycle of the fundamental output voltage. Multilevel inverters generate sinusoidal voltages from discrete voltage levels, and Pulse Width-Modulation (PWM) strategies accomplish this task of generating sinusoids of variable voltages and frequencies. Several techniques for the implementation of PWM for multilevel inverters have been developed.

Abstract: The area of the multiphase motor has experienced a significant growth in last decade numerous interesting development have been reported in the literature in this chain this paper is an attempt to mathematically model both three phase and six-phase induction motor for comparison of their characteristics. Using this mathematical modeling a Simulink model is created whose results shows that the six-phase induction motor can sustain more than four times the torque that can be sustained by three phase induction motor of same design parameters. The six-phase motor is better not just in torque handling capacity but it also has inherent advantages of the multiphase induction motor.

1) are derived first by algebraically solving the equivalent circuit shown in Fig. 2. These extreme values include maximum torque, maximum mechanical power, maximum power factor, maximum efficiency, and maximum electric power. It will be shown that the torque and mechanical power extrema can be expressed in analytical forms while the power factor, efficiency and electric power extrema need to be solved numerically. It will then be shown that these extrema can also be determined graphically using the circle diagram method. The circle diagram method is an old method but can still be found in some textbooks (e.g., [3]-[4]). The research into graphical methods for induction motor analysis is still active (e.g., [5][11]). One may consider that the circle diagram method is limited to qualitative evaluation because it cannot give accurate results. In fact, if the circle diagram method is carried out by a modern computer drawing tool that allows the user to draw geometric diagrams with parameters (i.e., coordinates, lengths, angles, etc.) to the accuracy of four decimal places, then the circle diagram method is able to give all the aforementioned performance extrema with required accuracy. Unlike the circle diagram method used in [10] and [11] that is based on the approximate equivalent circuit of induction machine and is limited to motoring mode of operation, the circle diagram method used in this paper is based on

Abstract— Conventional three-level discontinuous pulse-width modulation (DPWM) techniques are typically employed in variable frequency drive applications to reduce inverter switching losses and provide maximum benefit for load power factor angles in the range from 30° lagging to 30° leading. This paper proposes a series of DPWM templates for lower power factors and a generalized DPWM strategy for three-level T-NPC inverters operating with modulation indices lower than 0.5. With a change in the power factor, the proposed strategy adapts the inverter pulse sequence by combining different portions of the proposed DPWM templates within one fundamental cycle and ensures minimum switching instances during transitions. Consequently, the strategy perfectly aligns the no-switching durations of the inverter pulse-patterns with the respective load-current peaks, achieving a 50% switching loss reduction for all operating power factor angles (90° lagging to 90° leading) at modulation indices lower than 0.5. The paper provides an analytical evaluation of the proposed strategy on the three-level T-NPC inverter switching losses. The simulation and experimental results demonstrate the effectiveness of the proposed three-level generalized

DC motors are suitable for belt-driven applications and the applications where great amount of torque is required. In Train