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.

Fig. 11 shows a comparison of DPWM2O, DPWMLPF2 and GDPWMO at 0.4 modulation index. The inverter is operating with 160 Hz fundamental frequency and 7.68 kHz switching frequency. The output power factor angle is 45°. It can be seen that each strategy produces 32 pulses in one cycle. However, the clamping interval of the GDPWMO strategy is perfectly aligned with the line current peaks, whereas the DPWM2O and DPWMLPF2 strategies incurs switching instances around the current peaks.

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.

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.

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].

Now a days, the switching power supply market is flourishing quickly. The trend is for DC-AC converters with low cost, higher efficiency, power saving that enable maximum features. In this project, a single-stage three-switch buck-boost inverter is designed, where stepping up, stepping down and inversion operation will takes place in single stage. This proposed inverter will overcome all the drawbacks of traditional one. Coupled inductor plays a very important role in energy transfer and eliminates the use of line frequency transformer. As the inverter having only three switches, the controlling of switches also easier than conventional one. And it has also advantages like compact design, reduced switching losses, component size, and cost.

BLDC motors are a type of synchronous motor. This means the magnetic field generated by the stator and the magnetic field generated by the rotor rotate at the same frequency. BLDC motors do not experience the “slip” that is normally seen in induction motors. BLDC motors come in single-phase, 2-phase and 3-phase configurations. Corresponding to its type, the stator has the same number of windings. Out of these, 3-phase motors are the most popular and widely used. Brushless Direct Current (BLDC) motors are one of the motor types rapidly gaining popularity. BLDC motors are used in industries such as Appliances, Automotive, Aerospace, Consumer, Medical, Industrial Automation Equipment and Instrumentation. As the name implies, BLDC motors do not use brushes for commutation; instead, they are electronically commutated.

adapted to their area of applications, by allowing both hardware and software to be customized at very low cost[3], it has a key impact on hardware or software co-design and they are used as devices for rapid pro-to typing, and for final products[4]. This find application in sophisticated motor drive systems, such as fully integrated controllers, sensor less control, sensor less control with an extended Kalman filter algorithms, and adaptive fuzzy based controller[5]. Also in some application like Intelligent maximum power point trackers for photovoltaic applications, Realization of active power filter based on indirect

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.

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

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.

Switched reluctance motor (SRM) has merits of rigid and simple structure, simple converter circuit with fault tolerance, high starting torque, premium speed regulation performance, high speed capability, high torque to inertia ratio. However, the SRM suffers from noticeable torque ripple due to discrete nature of the torque production, acoustic noises, high nonlinear characteristics due to the doubly saliency structure. The nonlinearity in the operation of the SRM complicates the analysis as well as the control of the motor [1-5].

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

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.