A.B. Rey

A simpler and faster method for SVM implementation

Space vector modulation is perhaps the common technique mostly applied to drive three-phase voltage-source inverters. During every switching period it calculates three duty cycles in order to generate a suitable pulse sequence. This paper presents a new, faster and, most important, simpler method to compute these time values without using either trigonometric functions or even Clarke or Park transformations. The result is a light-weight algorithm easier to implement in small digital signal processors or microcontrollers. The relationship between SVM and PWM is also explained.

Comparative Analysis of the Techniques of Current Commutation in Matrix Converters

The devices of power used in matrix converters (M.C.) need some operation sequences to commute the current in a safe way. These operation sequences are what we denominate strategies of current commutation, being these more complex than in other converters. In this article a comparative analysis of the different strategies of current commutation will be carried out by means of simulation and they will be implemented in a experimental matrix converter to analyze its behaviour. As comparison criterion of the different strategies that have been used, the total harmonic distortion (THD), the efficiency of the converter, the maximum commutation frequency and the necessary hardware requirements for the implementation of the strategies.

A novel current control strategy for PWM inverters using the sliding mode techniques

Classical PWM techniques are replaced by current source sliding mode control (SMC) deciding the IGBTs status in real time by using a FPGA. Utility synchronization and inverter management is guaranteed by Park vector transformation. Three novel sliding strategies for current controlled PWM inverters are described, and several simulations show the performance of the inverter control.

Novel current source control strategies for 3-phase DC/AC power conditioners

Classical pulse width modulation (PWM) techniques are replaced by current source sliding mode control (SMC) computing the status for the three-phase power switches in real time. Synchronization with the mains and inverter management are guaranteed by Park vector transformation. Three novel sliding strategies for current source inverters are described, and the existing equivalence between the control of phase currents and phase to phase currents is shown. Several simulations show the performance of the inverter control.

Encapsulating connections on SoC designs using ASM++ charts

This article presents a methodology to encapsulate, not only the functionality of several SoC modules, but also the connections between those modules. To achieve these results, the possibilities of Algorithmic State Machines (ASM charts) have been extended to develop a compiler. Using this approach, a SoC design becomes a set of chart boxes and links: several boxes describe parameterized modules in a hierarchical fashion, other boxes encapsulate their connections, and all boxes are linked together using simple lines. At last, a compiler processes all required files and generates the corresponding VHDL or Verilog code, valid for simulation and synthesis. A small SoC design with two DSP processors is shown as an example.

Interpretation of the instantaneous frequency of phonocardiogram signals

Short-Time Fourier transforms, Wigner-Ville distribution, and Wavelet Transforms have been commonly used when dealing with non-stationary signals, and they have been known as time-frequency distributions. Also, it is commonly intended to investigate the behaviour of phonocardiogram signals as a means of prediction some oh the pathologies of the human hart. For this, this paper aims to analyze the relationship between the instantaneous frequency of a PCG signal and the so-mentioned time-frequency distributions; three algorithms using Matlab functions have been developed: the first one, the estimation of the IF using the normalized linear moment, the second one, the estimation of the IF using the periodic first moment, and the third one, the computing of the WVD. Meanwhile, the computing of the STFT spectrogram is carried out with a Matlab function. Several simulations of the spectrogram for a set of PCG signals and the estimation of the IF are shown, and its relationship is validated through correlation. Finally, the second algorithm is a better choice because the estimation is not biased, whereas the WVD is very computing-demanding and offers no benefit since the estimation of the IF by using this TFD has an equivalent result when using the derivative of the phase of the analytic signal, which is also less computing-demanding.

A methodology for teaching the integrated simulation of power systems by modeling with MATLAB/SIMULINK and controlling via a C-based algorithm

An adequate methodology to teach integrated simulation of power electronic systems is presented in this paper for undergraduate and postgraduate students, taking into account the advantages of SIMULINK blocksets for modelling, together with C algorithms for controlling, and MATLAB toolboxes for analysis and visualization. The power electronics devices and systems are modelled by using several blocks of the SimPowerSystems library of SIMULINK, whereas the control algorithms (the axes transformation, the utility observer, the link voltage regulator, the currents references generator, and the current source sliding mode control for the converter currents) are written in C and are integrated with SIMULINK via two S-Functions, which are explained in detail. The validity of the proposed methodology is demonstrated through several simulations of the vector control of a 3-phase AC/DC converter, working as an inverter, firstly, and as a rectifier, secondly.

A novel utility observer for current source PWM inverters with unitary power factor

A utility observer is used for utility-inverter (voltage-current) synchronization by using the Park vector transformation. A noncoupled expression for active and reactive powers is shown and unitary power factor is guaranteed whenever needed. Several simulations show the performance of the observer proposed.