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This paper deals with Wind Energy Conversion System (WECS) control equipped by Doubly-Fed Induction Generator (DFIG). Based on variable speed wind turbine and aerodynamic torque estimation, high order sliding mode controller is developed to improve the dynamic performances of WECS by producing the required electromagnetic torque generator. The desired DFIG torque is directly tracked using the proposed...
The emulation of synchronous machines is an attractive solution to improve the integration of distributed energy resources in weak grids. In this sense, synchronverters have been widely analysed in the literature, but their digital implementation has been seldom studied. This paper presents the discrete-time implementation of the control algorithms for a battery-supported synchronverter in a weak...
The open-ended winding configuration allows feeding an electric motor from two sides. If one of them is connected to an inverter closed on a floating capacitor, operating as an active power filter, it is possible to obtain several benefits over the traditional configuration, such as an extended field weakening speed range and a lower current ripple. However, the additional converter causes switching...
Synchronous machines exhibit, under normal operating conditions, torque oscillation problems. This work presents a study that proposes a methodology for the reduction of these oscillations. It was tested in a synchronous generator powered environment with DC voltage supplying power to a common bus in permanent regime, this bus has the presence of a nonlinear load. There are oscillating components...
This papers deals with the control of active and reactive powers in wind energy conversion systems (WECS) powered by dual-stator-winding squirrel-cage induction generators (BDFIG). In these systems, the MPPT technics based on a torque control present coupling with reactive power objectives. A High Order Sliding Mode MIMO control is proposed for satisfying the power objectives in a decoupled way. The...
A novel four quadrant operation control strategy of permanent magnet synchronous motor (PMSM) drive systems is proposed. In order to regulate precisely output direct current (DC) bus voltage and achieve the control of unity power factor, the exponential functional-based sliding mode reaching law (ESMRL), which adapts to the variations of the grid-side inverter and sliding mode surfaces, is developed...
This paper presents recently developed Variable Gain Super Twisting Algorithm (VGSTA) for Direct Power Control (DPC) of a grid connected Doubly-Fed Induction Generator (DFIG) system to regulate stator active and reactive power directly in stationary reference frame. Grid-connected DFIG system exhibit highly non-linear behaviour due to random wind fluctuations, uncertainties in machine parameters and...
Some aspects concerning the optimal design and sizing of an asynchronous traction motor are described. The motor must be integrated with a static converter in the traction system of a locomotive driving a multiple unit train. This drive system is aimed for light power applications, and the parameters necessary for the analysis of the regenerative braking system are also accounted for. An algorithm...
Modular multilevel converter (MMC) is one of the recent developed converter for high power applications. However, the major drawback of this converter in variable speed drives is that the capacitor ripple voltage increases at lower speed, when the load torque remains constant. This ripple voltage can be reduced by reducing the dc-bus voltage at lower speeds, while the capacitor voltages are maintained...
Medium voltage permanent magnet synchronous motor (PMSM) driven subsea pumps have the potential to improve system efficiency and reliability to lower the operating costs, and reduce the subsea pump module (PM) weight and size. These subsea pumps can be deployed in the well, in a dummy well or on the mudline in a skidded configuration. The higher speeds achieved by such motors, compared to the same...
The paper discusses the impact of air conditioning motor stalling in the Saudi electric grid. Slow voltage recovery after fault events is a result of high concentration of prone-to-stall motors in the grid. Multiple mitigation solutions are discussed from technical, regulatory, economical and planning perspectives.
This paper provides a solution for design of permanent magnet (PM) assisted synchronous reluctance machine (PMa-SynRM). Unlike interior PM machines, the PMa-SynRM is substantially a SynRM with a dominant reluctance torque. PMa-SynRMs are often designed by direct embedding magnets in a SynRM rotor to improve the performance over the original SynRM. However, the PM arrangements being more effective...
Direct-drive in-wheel motors have become an extremely attractive option for electric vehicles. Two kinds of motors are devised, Permanent Magnet Synchronous Motor (PMSM) and Permanent-Magnet Flux-Modulated Motor (PMFM), respectively. Keeping the same back EMF, current density and copper loss, this paper analyzes and compares torque density, torque ripple, flux-weakening performance, speed range, loss...
The doubly-fed reluctance machine is a viable substitute for the widely used wound rotor doubly-fed induction machine (DFIM) in adjustable speed slip power recovery applications (e.g. pump-type drives, high-inertia loads, wind turbines etc.). It may offer competitive performance to DFIM at equally low capital expenditure by adopting a similar fractional converter, but contributing further with much...
This paper describes the soft start and grid connection control strategies for high power synchronous compensator fed by low-voltage load-commutated inverters (LCI). In the start-up stage, field weakening method is used to make the motor start stably, and the back electromotive force (EMF) basically remain stable within the LCI withstand voltage at the same time. When the motor speed up to above the...
Hybrid excited axial field flux-switching permanent magnet (AFFSPM) (HEAFFSPM) machine is a novel stator-excitation hybrid excited synchronous machine, which combines the advantages of AFFSPM machine and wound-field excitation machine. In this paper, the structure feature of HEAFFSPM machine is analyzed, and the mathematical model is established. In order to improve the power factor of drive system...
This paper presents the design of an Interior permanent magnet (IPM) synchronous machine to improve machine performance by increasing saliency ratio and minimizing the leakage flux through the ribs and air barriers of an IPM machine. A bar-type IPM basic model is taken and two variables, variable 1 as factor-A and variable 2 as factor-B are analyzed. Factor-A is the radial distance of the rotor air...
This paper investigates an induction machine using a novel concept of a converter-fed rotor. The stator is directly connected to the grid while the rotor is fed by a converter with a floating capacitor over the dc-link. In earlier work this topology has shown to be capable of improving the power factor and efficiency of a 4-pole induction machine. This paper explores the possibility to improve the...
This paper presents an investigation into the effects of a novel rotor cut-off design on the performance of a synchronous reluctance machine. The rotor design consists of a sinusoidal lamination shape in the axial direction thereby varying the magnetic flux in the g-axis direction and reducing torque harmonics due to slotting effects. The presented study uses single-factor experimental design, with...
Common opened-loop I/f control method for permanent magnet synchronous motor(PMSM) has several defects in practice like the low efficiency, vulnerability in losing synchronization under sudden load circumstance. This paper presented a new closed-loop sensorless I/f control method for IPMSM drives. In order to achieve maximum torque per ampere(MTPA) status, the reactive power is observed to regulate...
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