Magnetic Modelling of Synchronous Reluctance and Internal Permanent Magnet Motors Using Radial Basis Function Networks

The general trend toward more intelligent energy-aware ac drives is driving the development of new motor topologies and advanced model-based control techniques. Among the candidates, pure reluctance and anisotropic permanent magnet motors are gaining popularity, despite their complex structure. The availability of accurate mathematical models that describe these motors is essential to the design of any model-based advanced control. This paper focuses on the relations between currents and flux linkages, which are obtained through innovative radial basis function neural networks. These special drive-oriented neural networks take as inputs the motor voltages and currents, returning as output the motor flux linkages, inclusive of any nonlinearity and cross-coupling effect. The theoretical foundations of the radial basis function networks, the design hints, and a commented series of experimental results on a real laboratory prototype are included in this paper. The simple structure of the neural network fits for implementation on standard drives. The online training and tracking will be the next steps in field programmable gate array based control systems

Convergence analysis and tuning of a sliding-mode ripple-correlation MPPT

The development of fast Maximum Power Point Tracking (MPPT) algorithms for photovoltaic (PV) systems with high bandwidth and predictable response to irradiation transients is attractive for mobile applications and installations under fast changing weather conditions. This paper proposes the convergence analysis of a sliding-mode version of the MPPT based on ripple correlation control (RCC). The contribution of the paper is a dynamic model, useful to derive a set of design guidelines to tune the sliding-mode RCC-MPPT and achieve a desired dynamic performance under irradiation transients, without a dedicated commissioning phase. The research is based on sliding control theory and it includes both the chattering phenomena analysis and a discussion on the effects of reactive parasitic elements in the PV module. The proposed analysis and design have been validated by Matlab simulations first and then with experimental tests on a 35 W panel with a boost converter charging a 24 V battery. The results support the effectiveness of the proposed modelling procedure and design guidelines, showing good agreement between the model prediction and the experimental transient response

An Effective Model-Free Predictive Current Control for Synchronous Reluctance Motor Drives

The performances of a model predictive control algorithm largely depend on the knowledge of the system model. A model-free predictive control approach skips all the effects of parameters variations or mismatches, as well as of model nonlinearity and uncertainties. A finite-set model-free current predictive control is proposed in this paper. The current variations predictions induced by the eight base inverter voltage vectors are estimated by means of the previous measurements stored into lookup tables. To keep the current variations information up to date, the three current measurements due to the three most recent feeding voltages are combined together to reconstruct all the others. The reconstruction is performed by taking advantage of the relationships between the three different base voltage vectors involved in the process. In particular, 210 possible combinations of three-state voltage vectors can be found, but they can be gathered together in six different groups. A light and computationally fast algorithm for the group identification is proposed in this paper. Finally, the current reconstruction for the prediction of future steps is thoroughly analyzed. A compensation of the motor rotation effect on the input voltages is proposed, too. The control scheme is evaluated by means of both simulation and experimental evidences on two different synchronous reluctance motors

Energy-efficient autonomous solar water-pumping system for permanent-magnet synchronous motors

This paper presents a novel stand–alone solar– powered water pumping system, especially suited for usage in rural or remote areas. The system is primarily designed to reduce both cost and complexity, while simultaneously guaranteeing opti¬mal utilisation of the photovoltaic generator. The use of standard hardware and control architectures ensures ease of installation, service and maintenance. The proposed solution consists of a water pump driven by a permanent magnet synchronous motor (PMSM), controlled by a conventional field oriented control scheme. The photovoltaic array is directly connected to the DC bus of the inverter, with no intermediate power conversion stages. A perturbation based extremum–seeking controller adjusts the motor speed reference to attain the maximum power point opera-tion of the photovoltaic array. Both simulations and experimental results on a full-scale prototype support the effectiveness of the proposed system

Motor Parameter-Free Predictive Current Control of Synchronous Motors by Recursive Least-Square Self-Commissioning Model

This article deals with a finite-set model predictive current control in synchronous motor drives. The peculiarity is that it does not require the knowledge of any motor parameter. The inherent advantage of this method is that the control is self-adapting to any synchronous motor, thus easing the matching between motor and inverter coming from different manufacturers. Overcoming the flaws of the existing lookup table based parameter-free techniques, the article elaborates the past current measurements by a recursive least-square algorithm to estimate the future behavior of the current in response to a finite set of voltage vectors. The article goes through the mathematical basis of the algorithm till a complete set of experiments that prove the feasibility and the advantages of the proposed technique

M.Zigliotto, "Space vector Fourier analysis of SVM inverters in the overmodulation range

Abstract -Voltage-source inverters with Space Vector Modulation (SVM) are largely adopted in power conversion for ac drives. In this contest, the pulse-width control in the overmodulation range is becoming a topic of considerable interest. The paper proposes a novel application of the Space Vector Fourier Analysis to the voltages produced by the SVM inverters operating in the overmodulation range. A direct derivation of the output voltage low-order harmonic content is given, and a unified and analytical comparison among different SVM inverter overmodulation strategies is enabled

Inferential processor based fuzzy control for an electric drive

The paper is aimed to illustrate the design and the implementation of Fuzzy Logic Controllers (FLCs) for electrical drives on the inferential processor OMRON FP3000. The fundamentals of the FLCs are preliminarily illustrated. A description of the inferential processor and a discussion about its capabilities and limitations for this field of applications is first given. Then, the design and the implementation of two different FLCs for the speed and current control of a DC motor drive is given. Experimental results are also included in the paper