Papers by Leandre Nneme Nneme
Electrical and electronic engineering, 2019
In this paper, we present harmonics compensation technique, by means of Instantaneous Powers (pq)... more In this paper, we present harmonics compensation technique, by means of Instantaneous Powers (pq) theory based on Self-Turning Filter (STF) in a stand-alone Photovoltaic System (PVS). Active Power Filters (APFs) used for this purpose are also dedicated to reactive power compensation. The STF is used to obtain DC components from instantaneous voltages or currents to compute reference currents extraction. These currents are injected in opposite phases with a Source voltage Inverter (VSI) for harmonics mitigation. Various simulation results obtaining in Matlab-Simulink environment, under ideal conditions, irradiance and/or temperature step change, sudden changes on non-linear loads, are introduced to show the effectiveness of this technique, by means of total harmonic distortions (THD) measurement.
American Academic Scientific Research Journal for Engineering, Technology, and Sciences, Jun 4, 2021
The aim of this study is to propose models for predicting skin temperatures and heat loss by evap... more The aim of this study is to propose models for predicting skin temperatures and heat loss by evaporation for the inclusion in the calculations of thermal comfort indicators in hot and humid areas, more particularly in sub-Saharan Africa. This will make it possible to complete the thermal comfort data for this climatic region, which for lack of it still uses the standard based on Fanger models, established mainly for the temperate zone (ISO 7730). The experiments were carried out on a representative sample of 24 people (men and women) in experimental buildings, located in the Douala-Cameroon region, representative of the hot and humid zone, as considered by numerous thermal balance references encountered in the litterature. The measurements of the ambient parameters and of the physiological parameters were carried out according to the recommended standards. 1008 skin temperature measurement points were performed on 3 levels of metabolic activity, in order to provide 72 individual average skin temperature values. Analyzes, statistical validation tests and comparisons were performed. We are able to present the most suitable prediction models, other than those of Fanger, for thermal comfort conditions in air-conditioned buildings in hot and humid areas of sub-Saharan Africa. It appears that the skin of people living in these regions has a higher thermal inertia, less water loss by diffusion or a higher skin barrier than that of people in temperate regions.
This paper presents the fault diagnosis of a three-phase induction motor using fuzzy logic, neura... more This paper presents the fault diagnosis of a three-phase induction motor using fuzzy logic, neural network and hybrid system. Detailed analysis during voltage unbalance, open phase, low voltage and overload motor fault using these strategies are presented. Stator currents were measured and their root mean square were derived. These values were used to train data. Each output of these diagnosis tools is used to determine the motor conditions whether it is in a healthy state or in a faulty one. A novel hybrid system is design and used in fault diagnosis. Simulation results show that hybrid systems give the best estimation of faults and can be therefore used in monitoring of induction motors with greater efficiency.
Journal Européen des Systèmes Automatisés, 2021
In this paper, we propose a novel hybrid algorithm based on MAX-MIN Ant System version of ant col... more In this paper, we propose a novel hybrid algorithm based on MAX-MIN Ant System version of ant colony optimization coupled with quadratic programming (MMAS-QP). Quadratic programming is used to optimize the Economic Dispatching process and MMAS for planning the switching schedule of a set of production units. The algorithm is implemented in MATLAB software environment for two systems, one is 4 generating units running for 8 hours, and the other is 10 generating units running for 24 hours. The impact of heuristic parameters on the behavior of the algorithm is highlighted through the parameters setting. Results obtained shows improved solution compared to several methods such as Modified Ant Colony Optimization (MACO), particle Swarm Optimization combined with Lagrange Relaxation (PSO-LR), Swarm and Evolutionary Computation (SEC), Particle Swarm Optimization combined with Genetic Algorithm (PSO-GA). The proposed method improves sufficiently the quality of the solution as well as the ex...
International Conference on Information Acquisition, 2004. Proceedings.
Boosted by trends such as Industrial IoT and Industry 4.0, industrial Ethernet networks (EtherNet... more Boosted by trends such as Industrial IoT and Industry 4.0, industrial Ethernet networks (EtherNet/IP, EtherCAT and PROFINET IRT as top-3 players) have been commonly deployed in industrial automation. The aim of this paper is to provide a practical guideline for selecting the right protocol in industrial networked control systems (NCSs) by comparing the performance of these protocols. Communication delays are discussed, formulated and evaluated with a study of a typical NCS. Simulation results demonstrate that with different frame packing, media access scheme, etc., EtherNet/IP, EtherCAT and PROFINET IRT offer different levels of real-time capabilities which lead to different control performance.
2012 Third International Conference on Computing, Communication and Networking Technologies (ICCCNT'12), 2012
High speed, low power SRAMs have become a critical component of many VLSI chips. This is especial... more High speed, low power SRAMs have become a critical component of many VLSI chips. This is especially true for microprocessors, where the on-chip cache sizes are growing with each generation to bridge the increasing divergence in the speeds of the processor and the main memory. Simultaneously, power dissipation has become an important consideration. A 64×64 SRAM memory system is designed, implemented and tested for correct read, write operation and performed the reconfiguration on memory system in order to optimize power. This paper presents a performance analysis of reconfigurable memory system for low power application. A 64×64 lena image is taken as test engine to validate the designed reconfigurable SRAM architecture. Simulations using TSMC 0.35um technology show that the SRAM cell read and write access times are 1.53ns and 1.93ns. Mentor Graphics ELDO and EZ-wave are used for simulations.
International Journal of Energy Technology and Policy, 2022
International Journal of Energy Technology and Policy
In this paper, a low cost duty-cycle modulation scheme is studied in depth and compared to the st... more In this paper, a low cost duty-cycle modulation scheme is studied in depth and compared to the standard pulse width modulation technique. Using a mix of analytical reasoning and electronics simulation tools, it is shown that under the same operating conditions, most characteristics of the proposed duty-cycle modulation scheme are better than those provided by a standard pulse width modulation technique. The simulation results obtained when testing both modulation control policies on prototyping systems, indicate that the proposed duty-cycle modulation approach, appears to be a high quality control policy in a wide variety of application areas, including A/D and D/A conversion, signal transmission and switching control in power electronics.
This paper presents a comparative study of SPWM (sine pulse width modulation) and SDCM (sine duty... more This paper presents a comparative study of SPWM (sine pulse width modulation) and SDCM (sine duty-cycle modulation) power inverters. A unified virtual workbench is built in Multisim framework, and used for fast simulation and rapid monitoring of results. From upstream to downstream, this workbench consists of: optional SDCM and SPWM divers; a single phase bridge power inverter, a 50 Hz filter and a load. The retained comparative criteria, rely on building hardware components, operating properties and the performance of the AC voltage delivered to the load in each case. As findings emerging from well tested prototyping systems, the SDCM-based inverter offers in most cases, smarter operating properties and better overall performance, compared to those provided by the SPWM-based inverter. Hence, the extended versions of SDCM for three-phase inverters, might become an emerging research area of control systems in power electronics . Keywords- SDCM; SPWM; drivers, workbench; simulation; ...
WSEAS Transactions on Circuits and Systems archive, 2018
In this paper, a novel SDCM (sine duty-cycle modulation) scheme for photovoltaic (PV) singlephase... more In this paper, a novel SDCM (sine duty-cycle modulation) scheme for photovoltaic (PV) singlephase power inverter is presented. Unlike popular SPWM (sine pulse width modulation) strategies, the SDCM control scheme consists of a minimum number or building components, while offering a robust feedback control topology. The main DC power to be converted, is delivered by an upstream PV panel. Then, a SDCM circuit with appropriate basic modulation frequency, is used as a switching driver for power MOSFETs of a single phase H-bridge inverter. The merits of the proposed SDCM control scheme, are proven using analytical developments, followed by relevant virtual simulations conducted on a prototyping power inverter within Multisim software framework. Moreover, the virtual simulation results obtained are presented, in order to show the high quality of the proposed class of SDCM control schemes for PV Single-phase power inverters.
International Journal of Scientific Research in Computer Science, Engineering and Information Technology, 2020
In this paper, a novel building algorithmic scheme of DDCM (duty-cycle modulation) drivers is pre... more In this paper, a novel building algorithmic scheme of DDCM (duty-cycle modulation) drivers is presented. It is modelled in the analog domain as a continuous time jump Markovian dynamic model, with a deterministic two-state Markov chain. An equivalent discrete jump dynamic model is computed using pole-zero matching transform. Then, the resulting digital iterative algorithm, consists of simple digital operators and structures. The proposed DDCM algorithm is simulated under Matlab framework, and implemented using Arduino IDE-C++ with uploading into an ESP32 system-on-chip (SoC) device. The monitoring device connected to the ESP32 via an USB communication cable is an Arduino/IDE virtual monitor. It is configured for 230400 bauds communication. A low cost ESP32-based DAC (digital-to-analog converter), is virtually implemented and well tested as a case study of the proposed new generation of DDCM drivers. Matlab digital simulation results and ESP32 processing and virtual monitoring result...
WSEAS Transactions on Circuits and Systems archive, 2018
In this paper, the chaotic phenomena are outlined in a class of simple NRO (negative resistance o... more In this paper, the chaotic phenomena are outlined in a class of simple NRO (negative resistance oscillator) or NCO (negative conductance oscillator) equivalently. Compared to most chaotic electronic schemes encountered in nonlinear dynamic systems theory and practice, the proposed class of chaotic circuits consists of simple piecewise linear NRO/NCO, involving a minimum number of building components and dynamic states. The feasibility of relevant chaotic phenomena is proven from the existence of their Van Der Pol dynamic models according to the least square estimation principle. Then, despite the simplicity of the 2nd order NRO/NCO, a relevant parameterization strategy associated with virtual simulation techniques, are used as key exploration means for creating relevant chaotic phenomena. Therefore, new strange chaotic attractors with 2D/3D shapes are created and presented. Moreover, a comparative study with a sample of existing chaotic NRO/NCO schemes, show that the proposed class ...
The DCM (duty-cycle modulation) is used in industrial electronics as a special technique for prod... more The DCM (duty-cycle modulation) is used in industrial electronics as a special technique for producing switching time-varying periodic waves, with variable pulse width and modulation period. As an implication, unlike the fixed period of a PWM wave, the cyclic ratio of a DCM signal changes as a function of the modulating input according to a known function. However, most existing research works related to DCM-based instrumentation systems, are limited to single-channel contexts. In this paper, a multichannel DDCM (Digital Duty-Cycle Modulation) scheme is developed. It consists of an extended pre-computed DDCM data map, which significantly reduces the overall DSP (digital signal processing) time, and a piece of dual DDCM counting logic with a downstream zero order holder per analog channel. It is used to build a well tested 4-channel FPGA-based signal generator with 10–12 bits resolution.
This paper presents a review of a multipurpose duty-cycle modulation (DCM) technology . A brief i... more This paper presents a review of a multipurpose duty-cycle modulation (DCM) technology . A brief introduction to switching modulation techniques is presented for the sake of well understanding of the innovative nature of the DCM architecture to be reviewed. The review is organized into numerous relevant application areas, including DCM-based instrumentation systems (i.e., DCM-based analog-to-digital conversion, DCM-based digital-to-analog conversion), DCM-based power electronic drivers (i.e. DCM-based Buck converters, DCM-based Boost converters, DCM-based power electronic inverters), and DCM-based digital transmission systems for arbitrary waveforms. Furthermore, the state-of-art evaluation as well as new research opportunities about the multipurpose DCM technology, are provided in order to outline possible patentable DCM control systems, to be dedicated in the future to electrical and electronics engineering markets .
This paper presents a design methodology and a virtual simulation framework, of the optimal feedb... more This paper presents a design methodology and a virtual simulation framework, of the optimal feedback control scheme for DCM ( duty-cycle modulation ) Buck choppers . The transfer function of an open loop DCM chopper, is built from the numerical analysis of a virtual step response, with Ref = 2 volts as step control input. Then, the optimal PID controller for DCM Buck Choppers is formulated and synthetized as a LQR ( Linear Quadratic Regulator ) equivalent control, and the associated Riccati equations is easily solvable using Matlab/LQR tool. As a relevant implication, the parameters of the corresponding optimal PID, are straightforwardly obtained from the LQR gains according to a LQR/PID equivalence principle, which is proven for a relevant class of second order dynamic systems. In addition, in order to show the feasibility of the designed optimal PID control scheme, a whole prototyping DCM Buck chopper with given operating conditions ( main DC supplied (12 V), load resistance ...
The novel digital-to-analog conversion technique studied in this paper, is founded on the digital... more The novel digital-to-analog conversion technique studied in this paper, is founded on the digital duty-cycle modulation principle. It consists of a simple digital duty-cycle modulation program loaded in the flash memory of a microcontroller and an external analog low pass filter. Both pulse width and modulation period, simultaneously evolve according to the variation of the modulating input. Then, under the
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Papers by Leandre Nneme Nneme