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Mexico City, Mexico

Flores-Marquez J.M.,ESFM IPN | Albor-Aguilera M.L.,ESFM IPN | Matsumoto-Kuwabara Y.,CINVESTAV | Gonzalez-Trujillo M.A.,ESCOM IPN | And 4 more authors.
Thin Solid Films

CdS polycrystalline thin films have been used as a window layer in CdTe, Cu(In,Ga)Se2and Cu2ZnSnS4solar cells; the specific optical and electrical properties of the CdS-partner play an important role in the photovoltaic device performance, so that one of the problems to be solved is to reduce the pin-hole density and intergrain cavities on the CdS surface. SnO2:F/soda-lime glass substrates (FTO) were treated with HCl, Ar and O2. CdS films were deposited on FTO substrates by using the chemical bath deposition technique and then CdS thin films were thermally annealed on CdCl2, Ar atmospheres and muffle at atmospheric ambient. Optical and morphological measurements revealed that the HCl treatment improves the CdS growth because the defect levels were reduced while the grain size is increased. The processed CdS-thin films were applied on CdTe solar cells and the photovoltaic efficiency was about 12% when the CdS thin films were thermally annealed in muffle at atmospheric ambient. © 2014 Elsevier B.V. Source

Aguilar-Ibanez C.,CIC IPN | Mendoza-Mendoza J.A.,CIC IPN | Suarez-Castanon M.S.,ESCOM IPN | Davila J.,ESIME IPN
International Journal of Control

This paper presents a smooth control strategy for the regulation problem of an uncertain system, which assures uniform ultimate boundedness of the closed-loop system inside of the zero-state neighbourhood. This neighbourhood can be made arbitrarily small. To this end, a class of nonlinear proportional integral controllers or PI controllers was designed. The behaviour of this controller emulates very close a sliding mode controller. To accomplish this behaviour saturation functions were combined with traditional PI controller. The controller did not need a high-gain controller or a sliding mode controller to accomplish robustness against unmodelled persistent perturbations. The obtained closed-solution has a finite time of convergence in a small vicinity. The corresponding stability convergence analysis was done applying the traditional Lyapunov method. Numerical simulations were carried out to assess the effectiveness of the obtained controller. © 2014 © 2014 Taylor & Francis. Source

De La Cruz Alejo J.,TESE | Oliva Moreno L.N.,ESCOM IPN
Program and Abstract Book - 2010 7th International Conference on Electrical Engineering, Computing Science and Automatic Control, CCE 2010

This paper presents a technique to solve mismatch compensation problems in current mirrors using the floating gate MOS transistor. To reduce mismatches, the tunneling and injection processes are applied in a 1.2μm CMOS process. It takes into account the long-term voltage storage as charge on the floating gate of a transistor pMOS. Experimental results justifying these processes are also including. The output current of the current mirror present successful results according to theorical analysis and achieving the mismatch compensation. © 2010 IEEE. Source

Aguilera M.L.A.,ESFM IPN | Marquez J.M.F.,ESFM IPN | Trujillo M.A.G.,ESCOM IPN | Kuwahara Y.M.,CINVESTAV | And 2 more authors.
Energy Procedia

CdS polycrystalline thin films have been used as window layer in solar cells; the quality of the CdS-partner plays an important role in the photovoltaic device performance. CdS thin films were deposited using Chemical Bath Deposition (CBD) and photoassisted-CBD technique. The SnO2:F substrates used in this work were treated with HCl (0.1 M) and some of themwere annealed in different atmospheres (Ar and O2). The properties of CdS thin films were influenced by the HCl treatment, position and the movement of substrates inside the reactor glass. CdS samples were deposited in areas of 4 cm2, 50 cm2 and 100 cm2; obtaining thin films with thickness of 35 - 300 nm with good crystalline quality and uniform morphology. All samplespresented optical transmittance around of 85 - 91% and average gap energy of 2.5 eV. © 2014 The Authors. Source

Aguilar-Ibaez C.,CIC IPN | Sira-Ramirez H.,CINVESTAV | Suarez-Castan M.S.,ESCOM IPN
Mathematical Problems in Engineering

We propose a flatness based approach for controlling the inverted pendulum cart system, under the assumption that the pendulum state is always located on a vicinity of its unstable equilibrium point. This is achieved by representing the original system, as a chain of integrators with an additive nonlinear state dependent perturbation. After discarding the small nonlinear perturbation, we may directly use design tools provided by the the flatness approach. The effectiveness and robustness of the obtained control law, which turned out to have a large domain of attraction, were numerically assessed in the context of stabilization and, also, for a reference oscillatory trajectory tracking task. © 2011 Carlos Aguilar-Ibez et al. Source

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