The commutation process causes current ripple to be generated in the drive system of brushless DC (BLDC) motor. This, in turn, leads to output torque ripple. Mechanical vibration and acoustic noise are its influences which are undesirable phenomenon in some applications. A new method is presented in this paper which reduces torque ripple and commutation period in the entire range of motor speed...

Ripple is a payment system and a digital currency which evolved completely independently of Bitcoin. Although Ripple holds the second highest market cap after Bitcoin, there are surprisingly no studies which analyze the provisions of Ripple. In this paper, we study the current deployment of the Ripple payment system. For that purpose, we overview the Ripple protocol and outline its security and...

Following learning, increased coupling between spindle oscillations in the medial prefrontal cortex (mPFC) and ripple oscillations in the hippocampus is thought to underlie memory consolidation. However, whether learning-induced increases in ripple-spindle coupling are necessary for successful memory consolidation has not been tested directly. In order to decouple ripple-spindle oscillations, h...

We formulate a continuum model for aeolian sand ripples consisting of two species of grains: a lower layer of relatively immobile clusters, with an upper layer of highly mobile grains moving on top. We predict analytically the ripple wavelength, initial ripple growth rate, and threshold saltation flux for ripple formation. Numerical simulations show the evolution of realistic ripple profiles fr...

this paper presents the method of reducing torque ripple of brushless dc (bldc) motor. the commutation torque ripple is reduced by control of the dc link voltage during the commutation time. the magnitude of voltage and commutation time is estimated by a neural network and optimized with an optimization method named particle swarm optimization (pso) algorithm analysis. the goal of optimization ...

This paper presents a new control structure to reduce torque ripple in switched reluctance motor. Although SRM possesses many advantages in motor structure, it suers from large torque ripple that causes some problems such as vibration and acoustic noise. In this paper another control loop is added and torque ripple is de ned as an objective function. By using fuzzy sliding mode strategy, the DC...

This paper analyzes the reason of Low-speed vibration in an electric vehicle, builds the mathematical equation of powertrain torsional vibration. Then, the model of torque ripple considering non-sinusoidal magnetic field distribution is built, orders and frequencies of torque ripple in PMSM is predicted. According to the relationship between the torsional vibration in low-speed of the electric ...

Maintenance activities cost about eighty percentage of the total project life cycle. But when we make changes at one place, changes propagate to other places as well leading to ripple Effect which leads to further increase in the cost of change. Object-Oriented Systems tend to be flexible but even then the ripple effect in these systems does exist. In this research work, we have proposed a comp...

We study the initial instability of flat sand surface and further nonlinear dynamics of wind ripples. The proposed continuous model of ripple formation allowed us to simulate the development of a typical asymmetric ripple shape and the evolution of a sand ripple pattern. We suggest that this evolution occurs via ripple merger preceded by several soliton-like interaction of ripples.

Switched-mode power supplies (SMPSs) are used to regulate voltage to a certain level. SMPSs have an inherent switching action, which causes the currents and voltages in the circuit to switch and fluctuate. The output voltage also has ripple on top of the regulated steady-state DC value. Designers of power systems consider the output voltage ripple to be both a key parameter for design considera...