C. Rando

Back EMF Sensorless-Control Algorithm for High-Dynamic Performance PMSM

In this paper, a low-time-consuming and low-cost sensorless-control algorithm for high-dynamic performance permanent-magnet synchronous motors, both surface and internal permanent-magnet mounted for position and speed estimation, is introduced, discussed, and experimentally validated. This control algorithm is based on the estimation of rotor speed and angular position starting from the back electromotive force space-vector determination without voltage sensors by using the reference voltages given by the current controllers instead of the actual ones. This choice obviously introduces some errors that must be vanished by means of a compensating function. The novelties of the proposed estimation algorithm are the position-estimation equation and the process of compensation of the inverter phase lag that also suggests the final mathematical form of the estimation. The mathematical structure of the estimation guarantees a high degree of robustness against parameter variation as shown by the sensitivity analysis reported in this paper. Experimental verifications of the proposed sensorless-control system have been made with the aid of a flexible test bench for brushless motor electrical drives. The test results presented in this paper show the validity of the proposed low-cost sensorless-control algorithm and, above all, underline the high dynamic performances of the sensorless-control system also with a reduced equipment.

A mathematical model to determine the electrical energy production in photovoltaic fields under mismatch effect

Among the electrical energy production systems from renewable sources, the photovoltaic one represents today one of the most efficient and technically tested choice. In this paper the Authors present a mathematical model that allows the maximization of the generated power of photovoltaic (PV) plants under unequally radiation conditions.

Dynamics photovoltaic generators: Technical aspects and economical valuation

The strategy adopted from many European nations and not, to entrust the electric energy production to differently energetic sources has determined an increment of the scientific research for the solar resource exploitation. These scientific community activities follows with attention from the entrepreneurial world have concentrated on the innovative techniques and methodologies of the source conversion, solar concentration and the directions device optimization. This job focuses its attention on the simple application of solar-track device, based on consolidated technologies. The diffused application of these dispositive, could be, shortly, an important increment of electricity generation energy from solar source. In particular this job estimates, with economic indices and for different size of the photovoltaic systems and of the solar-track devices, the increment of electricity generation to guarantee its economically favorable for the investor.

An electrochemical route towards the fabrication of nanostructured semiconductor solar cells

This work presents our preliminary results regarding an electrochemical process which allows the growth of nanostructured materials by means of nanopore templates. Also we analyze possible applications of this process to fabricate nanostructured semiconductors, such as CIGS, suitable for photovoltaic devices, and we consider the implications from the perspective of characterization techniques and device modelling when using such a technology.

Main Fuel Cells mathematical models: Comparison and analysis in terms of free parameters

This paper resumes the main mathematical models of Fuel Cells (PEM models). In particular, a comparison study of the various models introduced in the technical literature is presented and the dependency of the various model parameters is analyzed in different operating conditions. As the manifold of the model parameter is very wide and their determination is difficult, it is mandatory to introduce approximations and simplifications on which each model is based. The novelty of this work is the organization of the existing models in three categories with regard to the number of free parameters and to the dependency of such parameters on the different running conditions and the usage of a reference model in order to compare the difference between the latter once both in terms of fast execution of the simulation and care of the simulation results.

Sensorless control of permanent magnet synchronous motors for wide speed range applications

This paper deals with sensorless control of interior permanent magnet synchronous motors (IPMS) based on the estimation of speed and rotor angular position. The above estimate is based on the injection of high frequency stator currents able to generate a signal similar to that generated by a resolver connected to the axis of the motor. A new digital algorithm has been designed to demodulate the above signal whose implementation can be carried out on the same DSP that processes the control algorithm. In this paper a new scheme of speed and angular position estimator is proposed and justified on the theoretic point of view. The experimental results here shown validate the effectiveness of the sensorless control algorithm in all the operating situations concerning the whole speed and load torque ranges

Algebraic real-time algorithm for B-Spline sinusoidal pulse width modulation in three phase voltage source inverters.

In this paper a novel algebraic real-time algorithm for implementation of sinusoidal pulse width modulation (SPWM) based on B-spline carriers is introduced and discussed. B-spline functions are used as carrier signals with the aim to to reduce harmonic content of the three phase inverter output voltage. This algorithm eliminates the problem of B-spline recursive evaluation with convolution integrals or convolution sums in digital counterpart. The pulse pattern synthesis is made with the help pre-calculated duty cycle expressions. In this way the carrier signals have not to be really synthesized, hence the hardware and the whole inverter control system becomes cheaper, more reliable and affordable. The proposed control algorithm effectiveness is finally verified by means of numerical simulations in different operating condition (e.g. for different values of the amplitude modulation index and for different values of the power factor) of a three phase inverter. Different values for voltage and current total harmonic distortion (THD) are presented comparing the B-spline SPWM control with the classical SPWM control with triangular carrier signal.

Implementation and experimental validation of a real-time PWM algorithm based on B-Spline carriers for three phase voltage source inverters

This paper presents the implementation and experimental results of an algebraic real-time Sinusoidal Pulse Width Modulation algorithm (SPWM) based on B-Spline carriers. B-Spline functions are used as carrier signals with the aim to to reduce harmonic content of the three phase inverter output voltage. The presented algorithm eliminates the problem of B-Spline recursive evaluation with convolution integrals or convolution sums in digital counterpart. The pulse pattern synthesis is made with the help pre-calculated duty cycle expressions. In this way there is no real need to synthesize the carrier signal so the hardware and the whole inverter control system becomes cheaper, more reliable and affordable. The proposed implementation Algorithm effectiveness is finally verified by means of experimental tests in different operating condition (e.g. for different values of the amplitude modulation index and for different values of the power factor) of a three phase inverter.

Digital demodulation for fast set-up of sensorless PMSM electrical drives based on magnetic anisotropy

This paper presents a demodulation algorithm applied to the sensorless control of permanent magnet synchronous motors (PMSM). The sensorless control technique reported in this paper is based on the injection of high frequency voltages to the stator so that the motor currents contain information on the rotor position. This information is then extracted by an appropriate demodulation technique.

A novel correction method for a low cost sensorless control system of IPMSM electrical drives

In this paper a novel correction method for sensorless Field Oriented Control System of Brushless internal Permanent Magnet Electrical Drives is introduced discussed and experimentally validated. The novelty of this control system is the estimation of rotor speed and angular position is based on the back electromotive force space vector determination, without the aid of voltage probes. Actual voltage signals needed for estimation are replaced with the reference ones given by the current controller. This choice obviously introduces an error that have been vanished by means of a new compensating function or with the aid of data coming from experimental tests. Experimental verifications of the proposed sensorless control system were made with the aid of a flexible test bench for Brushless Motor electrical Drives. The test results presented in the paper show the validity of the proposed low cost sensorless control system and, above all, underline the good performances of the sensorless control system also with a so reduced equipment.