P-resonant control for the neutral point of three phase inverter

In this project, a Proportional resonant (PR) current controller is proposed to maintain a balanced neutral point for a three-phase four wire inverter, which can be used in microgrid applications. The neutral-point circuit consists of a conventional neutral leg and a split DC link. The neutral point is balanced with respect to the two DC source terminals (as required, in neutral-point clamped three-level converters) even when the neutral current is large so that the inverter can be connected to an unbalanced load. The controller, designed by using the Proportional resonant control techniques, which attain eliminate for the current flowing through the split capacitors. This leads to very small variation of the neutral point from the mid-point of the DC source, in spite of the possibly large neutral current. The simulation of inverter circuit, neutral-point and P-resonant has been performed using MATLAB/SIMULINK software. The simulation results confirm the validity of the proposed method, which can be seen as a promising that ensure P-resonant control suitable for microgrid applications

A general framework for the polynomiality property of the structure coefficients of double-class algebras

Take a sequence of couples $(G_n,K_n)_n$, where $G_n$ is a group and $K_n$ is a sub-group of $G_n.$ Under some conditions, we are able to give a formula that shows the form of the structure coefficients that appear in the product of double-classes of $K_n$ in $G_n.$ We show how this can give us a similar result for the structure coefficients of the centers of group algebras. These formulas allow us to re-obtain the polynomiality property of the structure coefficients in the cases of the center of the symmetric group algebra and the Hecke algebra of the pair $(\mathcal{S}_{2n},\mathcal{B}_{n}).$ We also give a new polynomiality property for the structure coefficients of the center of the hyperoctahedral group algebra and the double-class algebra $\mathbb{C}[diag(\mathcal{S}_{n-1})\setminus \mathcal{S}_n\times \mathcal{S}^{opp}_{n-1}/ diag(\mathcal{S}_{n-1})].

Q investment models, factor complementary and monopolistic competition

The observed fact that firms invest even if capacities are not fully employed does not fit well into most standard formalizations of optimal firm behavior. In this paper, the q investment approach is adapted to an imperfectly competitive economy where the representative firm is assumed to face demand uncertainty. Nominal rigidities and short-run factor complementarity are imposed as sufficient conditions to allow for the coexistence of investment and excess capacity. Since capacities are underemployed, marginal q is shown to diverge from average q. Finally, excess capacity subsists at steady state which makes it more than a shortrun phenomeno

Demand uncertainy and unemployement in a monopoly union model

The main concern of this paper is to show the importance of demand uncertainty in the determination of the "natural rate of unemployment". In the goods market there is demand heterogeneity -coming from preferences, and demand uncertainty -related solely to heterogeneity. Demand uncertainty is introduced in a monopoly union model where unions set wages at the first stage of the game, without knowing with certainty the demand for the good produced by the firm. Because the union assigns a positive probability at the event "underemployment equilibrium", it expects that the expected unemployment rate be positive. Since all the uncertainty is firm specific (i.e., there is not aggregate uncertainty), aggregate employment is equal to the union expected employment and then there is unemployment at equilibrium. In some islands the idiosyncratic demand shock is high and firms produce constrained by its full-employment capacity, but at the same time in the other islands the idiosyncratic demand shock is low and firms optimally produce less than its full-employment output

kk-partial permutations and the center of the wreath product Sk≀Sn\mathcal{S}_k\wr \mathcal{S}_n algebra

We generalize the concept of partial permutations of Ivanov and Kerov and introduce $k$-partial permutations. This allows us to show that the structure coefficients of the center of the wreath product $\mathcal{S}_k\wr \mathcal{S}_n$ algebra are polynomials in $n$ with non-negative integer coefficients. We use a universal algebra $\mathcal{I}_\infty^k$ which projects on the center $Z(\mathbb{C}[\mathcal{S}_k\wr \mathcal{S}_n])$ for each $n.$ We show that $\mathcal{I}_\infty^k$ is isomorphic to the algebra of shifted symmetric functions on many alphabets

New Lewis Structures through the application of the Hypertorus Electron Model

The hypertorus electron model is applied to the chemical bond. As a consequence, the bond topology can be determined. A linear correlation is found between the normalized bond area and the bond energy. The normalization number is a whole number. This number is interpreted as the Lewis's electron pair. A new electron distribution in the molecule follows. This discovery prompts to review the chemical bond, as it is understood in chemistry and physics

Path planning algorithm for a car-like robot based on cell decomposition method

This project proposes an obstacle avoiding path planning algorithm based on cell decomposition method for a car-like robot. Dijkstra’s algorithm is applied in order to find the shortest path. Using cell decomposition, the free space of the robot is exactly partitioned into cells. Then, the connectivity graph is created followed by calculating the shortest path by Dijkstra’s algorithm. This project also concerns the robot kinematic constraints such as minimum turning radius. Thus, kinematic modeling and Bezier curve have been used to obtain a feasible path. The algorithm is able to obtain a curvature bounded path with sub-optimal curve length while taking cell decomposition as reference skeleton. The C-space concept has been applied in this situation. The obstacles on the map are expanded according to the size of car-like robot, so that the robot could be treated as points on this map and the coordinates of the map is corresponding to these points. The simulation and experimental result shows the algorithm can obtain the collision free path which satisfies the curvature constraint and approaches the minimal curve length for a car-like robot