Showing papers on "Rotor (electric) published in 2014"
Patent•
14 Jan 2014
TL;DR: In this paper, a laser scanning module employs a scan mirror and magnet rotor subassembly supported by a stator structure using a pair of elastomeric wheel hinges, where the rotor support posts are aligned along a scan axis passing through the rotor frame.
Abstract: A laser scanning module employs a scan mirror and magnet rotor subassembly supported by a stator structure using a pair of elastomeric wheel hinges. The scan mirror and magnet rotor subassembly includes: a scan mirror and magnet rotor subassembly having a rotor frame having a pair of rotor support posts aligned along a scan axis passing through the rotor frame; a scan mirror mounted on the rotor frame; and a permanent magnet mounted on the rotor frame. The elastomeric wheel hinge includes a central portion having an aperture for passage and fixed attachment of one rotor support post, a plurality of elastomeric spoke portions extending from the central portion and radially extending from the central aperture to a circumferential rim portion connected to the outer end portion of each spoke portion so as to form the elastomeric wheel hinge.
333 citations
TL;DR: In this article, an inertial device that combines the frequency up-conversion principle with a rotating proof mass was presented for energy harvesting from human motion, in the form of piezoelectric beam plucking through magnetic coupling.
Abstract: Energy harvesting from human motion faces the challenges of low frequency and random excitation. One strategy that has been successful in the past is frequency up-conversion. This paper introduces an inertial device that combines this principle, in the form of piezoelectric beam plucking through magnetic coupling with a rotating proof mass. The advantages rotational systems can have for body movements are discussed. The prototype is described and tested in a real world environment during a running race and later on in a laboratory environment on a custom built linear excitation table. Throughout these tests it is confirmed that such a device can operate over a broad range of frequencies and under varying orientations, making it suitable for this intended application. Across frequencies between 0.5 and 4 Hz and accelerations between 1 and 20 m/s2 power outputs in the range of tens of microwatts were achieved, with a peak value of 43 μW at 2 Hz and 20 m/s2 when the rotor went into a continuous rotation.
276 citations
TL;DR: In this paper, a dual-stator spoke array (DSSA) VPM topology was proposed to achieve high power factor and high torque capability, and the performance of the DSSA VPM was evaluated based on finite element analysis, including power factor, torque density and cogging torque.
Abstract: Vernier permanent-magnet (VPM) machines are well known for high torque density but low power factor. This paper deals with the low power factor of VPM machines. The goal is not obtained by reducing the electrical loading or adjusting current advance angle but by proposing a novel vernier topology, i.e., a dual-stator spoke-array (DSSA) VPM topology. In this paper, the characteristics of the DSSA VPM topology, such as active part, auxiliary mechanical structure, and rotor anisotropy, are analyzed in detail. Performances are evaluated based on finite-element analysis, including power factor, torque density, and cogging torque. The results show that the DSSA VPM topology exhibits high power factor, viz., ~0.9, and significantly high torque capability. The verification of the mechanical structure scheme is also done in this paper. Finally, theoretical analyses are validated by the experimental results by a 44-rotor pole 24-slot DSSA VPM prototype.
269 citations
TL;DR: In this paper, the authors provide details of the design, analysis, and testing of an advanced interior permanent magnet (PM) machine that was developed to meet the FreedomCAR 2020 specifications.
Abstract: Electric drive systems, which include electric machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the petroleum dependence of the ground transportation sector. To have significant effect, electric drive technologies must be economical in terms of cost, weight, and size while meeting performance and reliability expectations. This paper will provide details of the design, analysis, and testing of an advanced interior permanent magnet (PM) machine that was developed to meet the FreedomCAR 2020 specifications. The 12-slot/10-pole machine has segmented stator structure equipped with fractional-slot nonoverlapping concentrated windings. The rotor has a novel spoke structure/assembly. Several prototypes with different thermal management schemes have been built and tested. This paper will cover the test results for all these prototypes and highlight the tradeoffs between the various schemes. Due to the high machine frequency (~1.2 kHz at the top speed), detailed analysis of various loss components and ways to reduce them will be presented. In addition, due to the high coolant inlet temperature and the fact that the machine is designed to continuously operate at 180 °C, detailed PM demagnetization analysis will be presented. The key novelty in this paper is the advanced rotor structure and the thermal management schemes.
209 citations
TL;DR: A novel, simple, fast, and systematic design procedure for a SynRM rotor with specific stator structure is developed and presented and can be competitively optimized with respect to an induction machine (IM) by a limited number of finite-element-method sensitivity analysis studies of the macroscopic design parameters.
Abstract: The complex rotor structure of the synchronous reluctance machine (SynRM ) is analyzed in this paper. Three macroscopic design parameters are introduced: insulation ratios in the d- and q -axes and the rotor slot pitch in the d-axis controller angle. These parameters are optimally linked to the microscopic and detailed SynRM rotor geometry (barriers, insulation layer and segments, magnetic layers inside the rotor) parameters (dimensions) by introducing and combining a general rotor arrangement with an analytical explanatory theory. This theory represents the anisotropic behavior of the SynRM rotor structure according to the literature. Based on these parameters, a novel, simple, fast, and systematic design procedure for a SynRM rotor with specific stator structure is developed and presented. A SynRM rotor can be competitively optimized with respect to an induction machine (IM) by a limited number of finite-element-method sensitivity analysis studies of the macroscopic design parameters. The machine torque can be maximized by finding the best insulation ratios, while the torque ripple can be minimized by determining the best rotor slot pitch in the d-axis. Both these optimizations can be defined independently of the stator structure. The method is validated by the design (using this procedure), prototype, and measurement of a specific SynRM machine with three barriers and a stator standard frame size of 160 [International Electrotechnical Commission (IEC)]. A heat-run test was done for both the SynRM and its corresponding IM with the same stator and test bench.
172 citations
TL;DR: In this article, a flux-intensifying permanent magnet type with low-coercive-force magnets is used in the design due to positive Id operation and reduced loaded Iq effects.
Abstract: This paper presents a design approach for interior permanent-magnet (IPM) machines with variable-flux characteristics using low-coercive-force magnets for improved efficiency and extended operating speed range. A flux-intensifying IPM type with is used in the design due to positive Id operation and reduced loaded Iq effects. Design considerations of machine structures and variable-flux machine attributes are discussed. In addition, leakage flux in a rotor is particularly designed to also obtain another flux-varying capability. Evaluation of the designed machine is provided by finite-element analysis simulations and experiments on a proof-of-principle machine. The designed machine shows benefits in increasing efficiency and speed range in a low-torque region when variable magnetization control of the low-coercive-force magnets or the design of the leakage flux proposed in this paper is implemented.
163 citations
TL;DR: This paper proposes a space-vector modulation (SVM)-based direct-torque control (DTC) scheme for a permanent-magnet synchronous generator (PMSG) used in a variable-speed direct-drive wind power generation system and greatly reduces the flux and torque ripples.
Abstract: This paper proposes a space-vector modulation (SVM)-based direct-torque control (DTC) scheme for a permanent-magnet synchronous generator (PMSG) used in a variable-speed direct-drive wind power generation system. A quasi-sliding-mode observer that uses a relatively low sampling frequency, e.g., 5 or 10 kHz, is proposed to estimate the rotor position and stator flux linkage based on the current model of the PMSG over a wide operating range. The optimal torque command is directly obtained from the estimated rotor speed for the DTC by which the maximum power point tracking control of the wind turbine generator is achieved without the need for wind speed or rotor position sensors. Compared with the conventional DTC, the proposed SVM-DTC achieves a fixed switching frequency and greatly reduces the flux and torque ripples, while retaining the fast dynamic response of the system. The effectiveness of the proposed SVM-DTC scheme is verified by simulation studies on a 1.5-MW PMSG wind turbine and is further verified by experimental results on a 2.4-kW PMSG with a 10-kHz sampling frequency.
151 citations
TL;DR: This paper develops the brushless dc (BLDC) motor sensorless control system for an automotive fuel pump that is based on a hysteresis comparator and a potential start-up method with a high starting torque.
Abstract: This paper develops the brushless dc (BLDC) motor sensorless control system for an automotive fuel pump. The sensorless techniques that are based on a hysteresis comparator and a potential start-up method with a high starting torque are suggested. The hysteresis comparator is used to compensate for the phase delay of the back EMFs due to a low-pass filter (LPF) and also prevent multiple output transitions from noise or ripple in the terminal voltages. The rotor position is aligned at standstill for maximum starting torque without an additional sensor and any information of motor parameters. Also, the stator current can be easily adjusted by modulating the pulse width of the switching devices during alignment. Some experiments are implemented on a single chip DSP controller to demonstrate the feasibility of the suggested sensorless and start-up techniques.
146 citations
TL;DR: In this article, a robust feedback linearization controller is developed, which sacrifices the controllability of the yaw state due to rotor failure to linearize the closed-loop system around a working point, where roll and pitch angles are zero and the angular speed around the vertical axis is a nonzero constant.
Abstract: In this paper, the problem of designing a control law in case of rotor failure in quadrotor vehicles is addressed. First, a nonlinear mathematical model for a quadrotor vehicle is derived, which includes translational and rotational dynamics. Then a robust feedback linearization controller is developed, which sacrifices the controllability of the yaw state due to rotor failure to linearize the closed-loop system around a working point, where roll and pitch angles are zero and the angular speed around the vertical axis is a nonzero constant. An H∞ loop shaping technique is adopted to achieve regulation of these variables around the chosen working point. Finally, an outer loop is proposed for achieving control of the linear displacement under the assumption of small angles approximation for the pitch and roll angles. The proposed control strategy allows the vehicle to use the remaining three functional rotors to enter a constant angular speed around its vertical axis, granting stability and representing an ...
138 citations
TL;DR: A sensorless control scheme is presented for induction motors with core loss, designed using a high order sliding mode twisting algorithm, to track a desired rotor velocity signal and an optimal rotor flux modulus, minimizing the power loss in copper and core.
Abstract: In this paper, a sensorless control scheme is presented for induction motors with core loss. First, a controller is designed using a high order sliding mode twisting algorithm, to track a desired rotor velocity signal and an optimal rotor flux modulus, minimizing the power loss in copper and core. Then, a super-twisting (ST) sliding mode observer for stator current is designed and the rotor flux is calculated, by means of the equivalent control method. Two methods for the rotor velocity estimation are then proposed. The first consists of a further super-twisting sliding mode observer for rotor fluxes, with the purpose of retrieving the back-electromotive force components by means of the equivalent control method. These components are functions of the rotor velocity which, hence, can be easily determined. The second method is based on a generalization of the phase-locked loop methodology. Finally, a simple Luenberger observer is designed, filtering the rotor velocity estimate and giving also an estimate of the load torque. The performance of the motor is verified by means of numeric simulations and experimental tests, where good tracking results are obtained.
128 citations
TL;DR: In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths.
Abstract: We present the space---time variational multiscale (ST-VMS) computation of wind-turbine rotor and tower aerodynamics. The rotor geometry is that of the NREL 5MW offshore baseline wind turbine. We compute with a given wind speed and a specified rotor speed. The computation is challenging because of the large Reynolds numbers and rotating turbulent flows, and computing the correct torque requires an accurate and meticulous numerical approach. The presence of the tower increases the computational challenge because of the fast, rotational relative motion between the rotor and tower. The ST-VMS method is the residual-based VMS version of the Deforming-Spatial-Domain/Stabilized ST (DSD/SST) method, and is also called "DSD/SST-VMST" method (i.e., the version with the VMS turbulence model). In calculating the stabilization parameters embedded in the method, we are using a new element length definition for the diffusion-dominated limit. The DSD/SST method, which was introduced as a general-purpose moving-mesh method for computation of flows with moving interfaces, requires a mesh update method. Mesh update typically consists of moving the mesh for as long as possible and remeshing as needed. In the computations reported here, NURBS basis functions are used for the temporal representation of the rotor motion, enabling us to represent the circular paths associated with that motion exactly and specify a constant angular velocity corresponding to the invariant speeds along those paths. In addition, temporal NURBS basis functions are used in representation of the motion and deformation of the volume meshes computed and also in remeshing. We name this "ST/NURBS Mesh Update Method (STNMUM)." The STNMUM increases computational efficiency in terms of computer time and storage, and computational flexibility in terms of being able to change the time-step size of the computation. We use layers of thin elements near the blade surfaces, which undergo rigid-body motion with the rotor. We compare the results from computations with and without tower, and we also compare using NURBS and linear finite element basis functions in temporal representation of the mesh motion.
TL;DR: In this article, the stator/rotor pole combinations, winding configurations, and electromagnetic performance of variable flux reluctance machines (VFRMs), which employ a doubly salient structure similar to switched reluctance machines, but with stator-located dc field windings, are investigated.
Abstract: In this paper, stator/rotor pole combinations, winding configurations, and electromagnetic performance of novel variable flux reluctance machines (VFRMs), which employ a doubly salient structure similar to switched reluctance machines (SRMs) but with stator-located dc field windings, are investigated. VFRMs with 12 stator poles are taken as examples to illustrate the method for determining the winding connections and winding factors. The back-electromotive force (EMF), self- and mutual inductances, cogging torque, static torque, torque ripple, and unbalanced magnetic force (UMF) are investigated by finite-element analyses. It is found that many stator/rotor pole combinations, i.e., 12/8 (which may be derived from the conventional three-phase SRM), 12/10, 12/11, 12/13, and 12/14, are feasible for the 12-stator-pole VFRMs. Among these pole number combinations, the 10- and 14-rotor-pole VFRMs can eliminate the inherent UMF in 6/5 and 6/7 VFRMs and exhibit more sinusoidal back-EMF waveforms and have higher torque density than an 8-rotor-pole VFRM, whereas the 11- and 13-rotor-pole VFRMs exhibit similar torque density as the 10- and 14-rotor-pole VFRMs, but with negligible cogging torque and torque ripple, albeit with UMF. Five prototype VFRMs with 12 stator poles and different rotor poles have been designed, manufactured, and tested to verify the analyses.
TL;DR: In this article, a 2D computational investigation of an augmented wind turbine is proposed and analyzed, and three parameters are carefully investigated: mesh resolution, turbulence model, and time step size.
TL;DR: In this paper, a coupled blade element momentum-based computational fluid dynamics (BEM-CFD) model is used to conduct simulations of groups of tidal stream turbines and evaluate the effects of turbine spacing and arrangement on flow dynamics and rotor performance.
01 Mar 2014
TL;DR: An analytical model for the bending stiffness of the bolted disk-drum joints is presented in this paper, where the model is applied to aero-engines with rotor disks and drums.
Abstract: Bolted joints are widely used in aero-engines. One of the common applications is to connect the rotor disks and drums. An analytical model for the bending stiffness of the bolted disk–drum joints i...
TL;DR: In this paper, a three-bladed H-rotor with unsymmetrical cambered S818 airfoil blades is investigated, which shows self-starting characteristics at many of the azimuthal angles.
TL;DR: In this article, a sensorless MPPT (fuzzy logic sensorless maximum power point tracking) method for WECS (wind energy conversion systems) was proposed, which greatly reduces the speed variation range of the wind generator which leads to the downsizing the PWM (pulse width modulation) back-to-back converters by approximately 40% in comparison with conventional techniques.
TL;DR: In this article, a double-sine wound rotor was proposed for the brushless doubly fed generator to reduce the harmonic contents of the rotor winding. But the design procedure and rules are given in detailed with the design example, and the validity of the proposed rotor structure is verified.
Abstract: The rotor structure is one of the key factors affecting the performance of the brushless doubly fed machine (BDFM). This paper presents a “double-sine” wound rotor for the brushless doubly fed generator to reduce the harmonic contents of the rotor winding. Ideally, so-called double sine is to make the magnetomotive force (MMF) space vector in one set of three-phase symmetric windings only containing two sinusoidal-waveform magnetic fields of different pole pairs. According to the principles of tooth harmonic and sinusoidal winding, the double-sine winding is designed to be constituted by double-layer unequal-turn coils. The design procedure and rules are given in detailed with the design example. The steady-state performance of a 60 kW prototype generator with double-sine wound rotor is analyzed by the simulation and experimental test, and the validity of the design method for proposed rotor structure is verified.
TL;DR: The automatic design of synchronous reluctance (SyR) machines is considered by means of finite-element analysis and multiobjective optimization algorithms (MOOAs) and the performance of three popular MOOAs is analyzed and compared.
Abstract: The automatic design of synchronous reluctance (SyR) machines is considered in this paper by means of finite-element analysis and multiobjective optimization algorithms (MOOAs). The research focuses on the design of the rotor geometry, which is the key aspect of the SyR machine design. In particular, the performance of three popular MOOAs is analyzed and compared in terms of quality of the final design and computational time. A procedure to minimize the computational burden of the optimized design process is introduced and applied to a three-layer and a five layer rotor. Two prototypes experimentally demonstrate the feasibility of the design procedure.
TL;DR: In this article, a deadbeat predictive current controller is proposed to accurately predict the required duty ratio for the PWM pulse for a given reference current in each digital time step over the entire speed range of operation.
Abstract: The paper presents a novel fixed switching frequency predictive current control method for switched reluctancemachines (SRM). The proposed deadbeat predictive current controller accurately predicts the required duty ratio for thePWM pulse for a given reference current in each digital time step over the entire speed range of operation. The pulsewidth depends on the operating conditions, machine parameters and the rotor position. The controller utilizes themachine inductance profile as a function of current and rotor position to accurately predict the required voltage. Thecontrol method is studied through computer simulation and followed by experimental validation. The method is suitablefor torque ripple sensitive applications requiring accurate tracking of a given current profile and mitigating theaudible noise due to the switching of the inverter.
04 Jun 2014
TL;DR: A dynamic model of the tilting rotor quadcopter vehicle is derived for flying and hovering modes that includes the relationship between vehicle orientation angle and rotor tilt-angle and a PD controller is designed to achieve the hovering and navigation capability at any desired pitch or roll angle.
Abstract: In this paper, the dynamic model of a tilting rotor quadcopter, i.e., a quad-rotor aerial vehicle with rotors that can tilt along one of its axes, is presented. The tilting rotor quadcopter provides the added advantage in terms of additional stable configurations, made possible by additional actuated controls, as compared to a traditional quadcopter without titling rotors. The tilting rotor quadcopter design is accomplished by using an additional motor for each rotor that enables the rotor to rotate along the axis of the quadcopter arm. This turns the traditional quadcopter into an over-actuated flying vehicle allowing us to have complete control over its position and the orientation. In this paper, a dynamic model of the tilting rotor quadcopter vehicle is derived for flying and hovering modes. The model includes the relationship between vehicle orientation angle and rotor tilt-angle. Furthermore, a PD controller is designed to achieve the hovering and navigation capability at any desired pitch or roll angle. The dynamic model and the control design is verified with the help of numerical studies.
TL;DR: The analytical model could be employed to assess the influencing factors of current harmonics and offers insightful guidance to the effective reductions of harmonic losses, torque ripples, and electromagnetic noises.
Abstract: The sideband current harmonic components would inhere in permanent-magnet (PM) synchronous machine systems driven by a voltage-source inverter with space vector pulsewidth modulation (SVPWM). However, these harmonics could potentially deteriorate the overall performance of the drive system by increasing the resultant losses, torque ripple, and electromagnetic and acoustic noises. The main sideband harmonic voltages and currents in PM synchronous machine driven by voltage-source inverter with SVPWM technique, are analytically derived and expressed in both stator and rotor frame. The experimental results are carried out to underpin the validity of the analytical model. The analytical model could be employed to assess the influencing factors of current harmonics. In addition, it offers insightful guidance to the effective reductions of harmonic losses, torque ripples, and electromagnetic noises.
TL;DR: A new topology of hybrid-excited flux-switching machine with excitation coils located in stator slots (or inner dc windings) with thermal stabilization is presented, making this topology an excellent candidate for high-speed applications.
Abstract: This paper presents a new topology of hybrid-excited flux-switching machine with excitation coils located in stator slots (or inner dc windings). After describing the three-phase structure to be investigated, the working principle is discussed, and the main electromagnetic performances are simulated by finite-element (FE) analysis. It is demonstrated that the air-gap field can be easily controlled, which is interesting for variable-speed applications. Finally, a prototype having 12 stator poles and different rotor tooth numbers (10 or 14) was built. Experiments were performed, validating the FE simulations and the operation principle. Finally, the thermal behavior of the prototype machine is investigated through experiments. It is shown that, up to 12 000 r/min, the thermal stabilization is achieved, making this topology an excellent candidate for high-speed applications.
TL;DR: The results confirm that the proposed magnet-skewing approaches can significantly reduce the cogging component as opposed to reference AFPM motor with unskewed magnets and help to improve the torque quality of the disk motors.
Abstract: Minimizing cogging torque in designing axial-flux permanent-magnet (AFPM) motors is one of the main issues which must be considered during the design process. This paper presents several cost-effective magnet-skewing techniques to minimize cogging torque components in double-rotor AFPM motors. Rotor-side cogging torque minimization methods are examined in detail with major focus on magnet-skewing approach, and several cost-effective alternative skewing techniques are proposed. A detailed comparison of magnet-skewing approaches is provided. A prototype AFPM motor with different rotor structures is built based on the analyses. Analyses are then validated with experimental results, and the influence of cogging torque component on torque quality of AFPM motors is explored. The results confirm that the proposed magnet-skewing approaches can significantly reduce the cogging component as opposed to reference AFPM motor with unskewed magnets and help to improve the torque quality of the disk motors.
TL;DR: In this article, the authors used a 1:20th scale 3-bladed horizontal axis TST at a large towing tank facility to measure rotor thrust and torque whilst one blade was instrumented to acquire blade root strain, azimuthal position and rotational speed all at high frequency.
TL;DR: In this article, a closed-form solution for the aerodynamic damping of HAWTs responding dynamically in the fore-aft and side-to-side directions is presented.
Abstract: Aerodynamic damping has an important effect on the seismic response of horizontal axis wind turbines (HAWTs). Some researchers have estimated that aerodynamic damping in operational HAWTs is ∼5% of critical in the fore-aft direction (i.e., perpendicular to the rotor and parallel to the prevailing wind). In most recent studies, dynamic analyses of HAWT towers under seismic loads have neglected aerodynamic damping, and this assumption has significant implications in the predicted seismic response. This paper presents a closed-form solution for the aerodynamic damping of HAWTs responding dynamically in the fore-aft and side-to-side directions. The formulation is intended as a convenient method for structural earthquake engineers to include the effect of aerodynamic damping in the seismic analysis of HAWTs. The formulation is based on blade element momentum theory and is simplified by assuming a rigid rotor subjected to a steady and uniform wind oriented perpendicular to the rotor plane. This paper ex...
TL;DR: The optimal VIPMM with assisted barriers shows the substantially improved performance compared with a conventional design, and is optimized by algorithms, such as the kriging method and genetic algorithm for improving the torque characteristics and efficiency.
Abstract: This paper performs a study on the optimal design of V-type interior permanent magnet motors (VIPMMs), in which the rotor is equipped with assisted barriers for the improvement of average torque and torque ripple. The approach differs from the conventional interior permanent magnet motors, in which the reluctance torque due to saliency reaches a maximum value at a current phase angle located 45 electrical degrees with respect to the maximum value obtained from the magnetic torque produced by the rotor magnets. The adoption of assisted barriers is employed to improve the torque production by creating rotor asymmetry to allow the reluctance torque and the magnetic torque reach a maximum value near or at the same current phase angle. To evaluate the contribution, the frozen permeability method is utilized to segregate the torque into its reluctance and magnetic torque components. First, an iterative optimization is performed on a concept design of a 6/4 VIPMM for demonstrating the design principle based on finite element method. Then, the VIPMM is further optimized by algorithms, such as the kriging method and genetic algorithm for improving the torque characteristics and efficiency. As a result, the optimal VIPMM with assisted barriers shows the substantially improved performance compared with a conventional design.
TL;DR: The Blind Test 2 workshop on wind turbine simulation was organized by Norcowe and Nowitech in Trondheim, Norway in 2012 as discussed by the authors, where a wide range of simulation models, such as a LES coupled with an actuator line rotor model, RANS using an actuators disc, U-RANS models applied to fully resolved turbine model geometries, as well as a vortex panel method, were presented.
TL;DR: The proposed self-commissioning method of electrical machine parameters at standstill only using a voltage source inverter fed drive is promising and robust to extract the resistance information from the gradient coefficient of the voltage variation.
Abstract: Offline parameter identification of permanent magnet synchronous machines (PMSMs) is essential for proper tuning of the controller and position observer for general-purpose drives with sensorless control. This paper proposes a self-commissioning method of electrical machine parameters at standstill only using a voltage source inverter fed drive. The influence of inverter nonlinearities including the effect of parasitic capacitance, which may cause estimation error, is analyzed. And an error model of inductance identification considering different rotor positions is established. Along with high-frequency sinusoidal signal, a supplementary direct current signal is injected into the estimated direct-axis to attenuate the inductance identification error. In addition, a compensation strategy based on the error model is adopted to enhance the accuracy of inductance identification. For stator resistance identification, the linear regression method is adopted to overcome the influence of inverter nonlinearities by injecting the linearly increasing current signal. The proposed method is promising and robust to extract the resistance information from the gradient coefficient of the voltage variation. The effectiveness of the proposed self-commissioning scheme is validated on a 22-kW PMSM drive.
TL;DR: In this article, the authors proposed an efficient control strategy to improve the fault ride through (FRT) capability of doubly fed induction generator (DFIG) during the symmetrical and asymmetrical grid faults.