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This paper is focused on the design of Axial Flux Permanent Machine (AFPM) tailored for low-speed high-torque applications. In particular, the design procedure is developed starting from a tooth concentrated winding topology; given its high reliability, this is an optimal solution in the context of electric torsional damping applications, where high torque values and good dynamic performance are required...
The paper deals with the vector control of two surface-mounted permanent-magnet (PM) synchronous-motors in configuration “single-inverter dual-motor”, operating also with unbalanced loads. Since this structure is justified by the objective of obtaining low cost drives, a low computation burden sensorless method is proposed in order to further reduce the system complexity. A very simple algorithm for...
The paper deals with ball screw actuators used for the electric steering of nose landing gears in civil aircrafts. Design options and performance analyses are carried out with reference to actuators composed by ball screws coupled with two multi-stage axial-flux permanent magnet motors, which are fed by two separate inverters. A redundant configuration of the drives is developed in order to increase...
This paper is focused on the design of a PMSM for the electric steering of a nose landing gear. The traditional hydraulic steering systems utilized in a nose landing gear are usually based on a rack and pinion solution with two hydraulic pistons at the external sides. The main idea proposed in the paper is the substitution of the hydraulic steering system with an electric steering system based on...
With reference to light railways transportation systems, in the paper a comparison is carried out between vehicles equipped with Induction Motor (IM) drives and Permanent Magnet (PM) brushless motor drives. The attention is particularly focused on the deceleration phase of the speed diagram, which consists of an interval of “coasting” followed by a braking interval. The analyses carried out aim to...
The paper deals with acoustic noise in permanent magnet synchronous motors (PMSM) with tooth concentrated armature windings. In particular, the noise emitted by this kind of motors is investigated with reference to high-torque low-speed applications. In these cases, due to the high number of poles, the stator yoke is usually thin and it is characterized by low natural frequencies that could lead to...
The paper presents an advanced solution for power supply and power quality improvement of isolated AC passive networks. The embedded system consists of a Self-Excited Induction Generator (SEIG) and a Static Var Compensator (SVC) specifically designed for the considered application domain. The SVC is composed by two legs and with an LC filter is linked to the three phase passive network. A proper SVC...
The paper deals with the control of three-phase voltage source rectifiers (VSRs) with an arbitrary number of voltage levels. By means of an approach borrowed from the “Direct Torque Control” of AC drives, the paper presents an enhanced direct power control (DPC) strategy for VSRs which directly controls both active (P) and reactive (Q) line power by considering the values of their time derivatives...
In this paper a solution is proposed for contra-rotating propellers in electric unmanned aerial vehicles. It is based on a direct drive system where the contra-rotating blades are directly fixed on the rotors of an axial-flux permanent magnet motor. The latter one is constituted by two external rotors and a single internal stator divided in two different sides. The study is focused on a 6 slots-4...
The paper analyzes and compares main features and performance of two different kinds of active front ends employed in high power induction motor drives. The two considered topologies of Voltage Source Rectifiers (VSR) are: A) two-level four-wire; B) three-level three-wire in Neutral Point Clamped configuration. Reference is made to a Direct Torque Control strategy, which can produce critical unbalanced...
This paper presents a control technique for smoothing voltage oscillations in the sub-modules of Modular Multilevel Converter during start-up operations of high-power medium-voltage induction motor drive. At steady-state, the power fluctuations in each sub-module at fundamental and 2nd harmonic frequencies generate capacitor voltage oscillations which are much higher as the current frequency decreases...
The rail traffic in Europe is increasing in frequency. As a result of this, all the countries are updating their power supply system involving the use of high-power static converters. Moreover, the high required power implies the use of medium voltage (MV) supply chains (i.e. 15–25 kV) while the traction drives are operated at voltages of some kV. In order to adapt the two voltage levels, an on board...
A fast and effective control of three-phase PWM-Rectifiers is presented in the paper, with reference to multilevel converter topologies. The presented strategy con be considered a “Direct Power Control” (DPC) because it is devoted to the direct control of active and reactive line-power, using a technique very similar to the well-known “Direct torque control” (DTC) of AC drives. An interesting aspect...
In this paper a power converter based on a modular multilevel topology is discussed. The Modular Multilevel Converter (MMC) is one of the emerging technology for high- or medium-voltage transformerless power conversion. The paper presents a space vector modulation technique developed for a MMC with arbitrary number of voltage levels; the presented technique integrates the modulation of the homopolar...
In this paper an analysis of a power converter based on a modular multilevel topology is discussed. A mathematical model of the MMC is developed in order to evaluate its dynamic behavior and to better understand the incidence of the circulating current phenomenon which could compromise converter performance in variable speed drive applications. In fact, if such problem is not properly addressed reliability...
An high performance control technique of dc-brushless drives is presented in the paper, with the aim to considerably reduce current and torque ripples. The proposed control algorithms are very simple and are separately pointed out for “two phase on” and “three phase on” operations, i.e. either far or during the commutation of two consequent armature phases. They can be successfully used in those dc-brushless...
This paper deals with the control of small-power wind turbine using fixed-pitch blades. A three-phase permanent magnet (PM) brushless generator is connected to the grid through a double stage converter: active rectifier (VSR) + d.c.-link + inverter (VSI). A very simple and effective control strategy of the generation set (PM generator +VSR) is presented; it is mainly aimed to extend the wind-turbines...
The paper discusses the design and global performance of a cogeneration unit suitable for distributed energy conversion based on an automotive internal combustion engine, which is a spark ignition methane fuelled unit, previously converted from a Diesel engine and chosen on the market as an efficient, low cost energy powerplant, to be adopted for different applications (such as domestic and commercial)...
A speed and high resolution position identification algorithm, suitable for brushless drives, is presented in this paper. The algorithm, which is developed basing upon the Popov's Hyperstability Theory, guarantees the convergence of the estimated signals to their corresponding actual values by means of the measured currents. The algorithm is proposed for brushless DC (BLDC) motors which are characterized...
With reference to medium-voltage grid-connection of large photovoltaic (PV) plants, the paper proposes and analyses a high performance solution based on a power electronic transformer (PET). It Includes dc-links and multilevel converters either in low-voltage or in high-voltage side, and a medium-frequency (MF) transformer. Together with the very reduced sizes of the whole conversion apparatus, an...
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