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In this paper, a torque control algorithm of a Permanent Magnet Synchronous Generator (PMSG) for Direct Drive Wind Turbines (DDWTs) is proposed. In particular, a twelve- phase PMSG with four independent three-phase output subsystems has been considered with the aim of improving the DDWT torque management, energy efficiency, power generation and reliability; these goals are achieved by means of the decoupled control of each three-phase subsystem which the generator is split in. Hence, a novel coordinate transformation and the synthesis of the proposed master control algorithm are introduced: this last one allows the independent management of the reference currents of each subsystem and, thus, permits the development of an efficient variable speed wind turbine control. In addition, using the proposed DDWT, a novel topology of Continuous Medium Voltage Distribution system (CMVD) for a wind power plant is presented. In particular, the DC subsystems power outputs are connected by means the proposed CMVD to a centralized cascaded H-Bridge inverter structure, which is the only interface between the electric power transmission network and the wind power plant. The goodness of the proposed control algorithm is verified by means of a simulation study carried out in the Matlab Simulink environment, whose results are presented in the paper. [ABSTRACT FROM AUTHOR]

In this paper, a predictive Direct Torque Control (DTC) of an Induction Motor (IM) drive is presented. Although the control uses stator flux and current vectors as state variables, a novel set of variables have been introduced in order to directly manage torque, stator flux and current magnitude variations in each sampling time interval. Then, the existence domain of the above mentioned variables in each sampling time interval is determined and depicted graphically, together with the inverter voltage saturation and current limitation constraints. As a result, the proposed predictive control algorithm allows a better tracking of the IM reference torque profile than that achievable by means of the traditional DTC technique, especially in terms of current and torque ripple. The effectiveness of the proposed predictive DTC algorithm is verified by simulating an IM drive by means of the Matlab Simulink tool. The simulation results, which also refer to the case of the traditional constant switching frequency DTC, highlight the good performance of the drive, especially referring to torque ripple and to low speed operation. [ABSTRACT FROM AUTHOR]

An EMI modelling of heat sinks employed in Switching Mode Power Supplies (SMPSs) is presented in this paper. In fact, the capacitive coupling between electronic power devices and their heat sinks generally lead to impulsive current circulation in the latter, making them able to generate conducted electromagnetic noise and/or to emit as antennas. Such electromagnetic noise may give rise to the incorrect electronic circuits and control system operations. Hence, the proposed heat sinks model is developed in order to evaluate these effects, aiming to be an useful tool in order to avoid system faults and to guarantee the compliance to EMC standards. In particular, the proposed model allows the achievement of the resonance frequency of a heat sink in a closed analytical form. The results obtained by employing the proposed modelling procedure is properly compared with those achieved by means of finite element investigations, highlighting the effectiveness of the proposed method. This is also corroborated by the experimental studies carried out in an EMC laboratory. [ABSTRACT FROM AUTHOR]

The paper deals with a high performance single-stage three phase inverter for grid connected PV systems. In the paper a current control algorithm is developed so that the proposed configuration can convert the solar dc power into high quality ac power while tracking the maximum power from the PV array, ensuring active and reactive power flow control, higher efficiency, low cost and compact size. Moreover total harmonic distortion of the current fed into the grid is very low with respect to the IEEE standard. In the paper a full analysis of the proposed system is presented and numerical results for different reference values of active and reactive power have been shown and discussed. [ABSTRACT FROM AUTHOR]

A predictive control of a brushless DC generator is presented in this paper. The tracking characteristic of the prime-mover is considered for setting the reference value of the electromagnetic torque developed by the generator. This reference is assumed in order to determine the switching pattern of the AC/DC converter, at each sampling period, under minimum Joule losses and minimum torque ripple constraints. In order to highlight the improved performances achievable by means of the proposed predictive control algorithm, two cases are considered: in the first one, the generator supplies a resistive load as in standalone applications, whereas, in the second one, it is connected to a constant voltage DC grid. Hence, the respective conversion systems are computer simulated in the Matlab Simulink environment and the results are compared to those of the traditional systems. The comparison reveals that, in both cases, the torque ripple minimization is achieved and more power can be delivered by using the proposed control technique with respect to those of traditional systems. [ABSTRACT FROM AUTHOR]

In the paper an interleaved soft switching dc-dc converter for applications in electric vehicle is proposed. The used topology raises the efficiency and the power density of the dc/dc converter minimizing switching losses by adopting a simple auxiliary active clamping circuit. Such auxiliary circuit is operational regardless of boost or buck mode of operation. The configuration guarantees fixed switching frequency, active clamped zero voltage switching operations of the main switches and bidirectional power flow. ZVS operations are guaranteed with wide load range. In the paper the operating principle, soft-switching conditions and steady state analysis are presented. A 27 kW prototype is designed and simulation results to verify the theoretical analysis are provided. [ABSTRACT FROM AUTHOR]

In the paper two control techniques are compared respect to the traditional field oriented approach (F.O.), in order to define the range of applicability of each one. Targets of the different controls are to achieve a vector control and to generate firing commands for the quasi resonant inverter (QRI), that guarantee soft switching of the inverter switch, improving the dynamic response of the whole system. These targets will be obtained by means of a state feedback approach. [ABSTRACT FROM AUTHOR]

A novel modulation technique suitable for the current control of brushless DC drives under commutation is presented in the paper. The pulse width of the chain voltages are determined by means of a predictive algorithm under the constraints of minimum Joule losses and torque ripple free commutation. At maximum speed the torque ripple appears but is lower than that of six step operation. The proposed technique leads also to higher mean torque than that of traditional six step operation. Simulation results highlight the better performance of the drive controlled by the propose algorithm with respect to that of the traditionally controlled drive. [ABSTRACT FROM AUTHOR]