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This paper presents the developments of sensorless control of interior permanent magnet synchronous machine (IPMSM) for last 10 years, which could be divided into the past and the present for each 5 years. Several popular methods developed for last 10 years would be described and evaluated, and the limitations with the methods are discussed. In the past a concept extended EMF (EEMF) was introduced and it can model IPMSM as a non-salient motor, meaning that the representation of IPMSM in the esti

In this paper, the theoretical analysis of the position estimation error in position-sensorless operation using pulsating square wave signal injection is presented. The purpose of this paper is to analyze the phenomenon that the position estimation performance varies depending on the injection frequency. Mathematical derivation supported by simulation and experimental results shows that, in no-load condition, the voltage distortion induces position estimation error with 3rd-order harmonics if th

In this paper, new model-based sensorless control methods are proposed that include independent estimations of position and speed errors, and compatible position and speed estimators. Using the proposed position estimator, a unity transfer function can be achieved from the actual position to the estimated position, eliminating the effects of load disturbances. This implies that the position error would ideally be zero, even in a transient state. In addition, the effects of parameter and voltage

This paper presents an online maximum torque per ampere (MTPA) control that considers both magnetic saturation and cross-magnetization effects of interior permanent-magnet synchronous machines (IPMSMs). For IPMSM drives, especially in torque-controlled applications, torque accuracy and high-efficiency operations are important issues. They can be dealt as a constrained optimization problem to satisfy both torque reference tracking and loss-minimizing operation. In this paper, nonlinear simultaneo

This paper analyzes and compares position estimation performances of fundamental-model-based sensorless control methods considering the effects of inverter nonlinearities and parameter estimation errors. Based on the investigation of four conventional sensorless control algorithms, estimated position error from each algorithm is represented in a quantitative manner. This representation is helpful in understanding how the error influences the position estimation performance. And, it is revealed t

Nowadays, a Line Commutated Converter (LCC)-HVDC is a mature technology with decades industry experience. Even though it's with several advantages such as higher reliability, lower cost, and higher efficiency, it presents some drawbacks such as large converter station size and lack of black starting capability. So the LCC-HVDC is not suitable for some applications in which black starting capability is necessary or high power density is highly emphasized. A LCC-Voltage Source Converter(VSC) hybri

This paper proposes a compensation method for precise position-sensorless control using high-frequency pulsating voltage injection and the criterion for applicability of the proposed compensation method is discussed. Theoretical background of the proposed 3-dimensional compensation table as well as the implementation method is described and it is disclosed that the real rotor position and the convergent position should have one-to-one relationship for precise estimation of the rotor position. Al

Concentrated hard-sphere suspensions in the liquid and crystal coexistence region show a unique nonlinear behavior under a large amplitude oscillatory shear flow, the so-called strain stiffening, in which the viscosity or modulus suddenly starts to increase near a critical strain amplitude. Even though this phenomenon has been widely reported in experiments, its key mechanism has never been investigated in a systematic way. To have a good understanding of this behavior, a numerical simulation wa

The local shear stress of non-Brownian suspensions was investigated using the lattice Boltzmann method coupled with the smoothed profile method. Previous studies have only focused on the bulk rheology of complex fluids because the local rheology of complex fluids was not accessible due to technical limitations. In this study, the local shear stress of two-dimensional solid particle suspensions in Couette flow was investigated with the method of planes to correlate non-Newtonian fluid behavior wi

In this paper, new model-based sensorless control methods are proposed, including estimation methods for the position and speed errors and compatible position and speed estimators. In proposed methods, the speed error is estimated as well as the position error in the conventional model-based sensorless methods. By the proposed methods, unity transfer function from actual position to estimated position can be achieved eliminating the effects of load disturbances. It means that the position error

Displacive transformations in colloidal crystals may offer a pathway for increasing the diversity of accessible configurations without the need to engineer particle shape or interaction complexity. To date, binary crystals composed of spherically symmetric particles at specific size ratios have been formed that exhibit floppiness and facile routes for transformation into more rigid structures that are otherwise not accessible by direct nucleation and growth. There is evidence that such transform

We carry out a numerical study to investigate the dynamics of non-Brownian hard-sphere suspensions near the liquid and crystal coexistence region in small to large amplitude oscillatory shear flow. The first normal stress difference (N1) and related rheological functions are carefully analyzed, focusing on the strain stiffening phenomenon, which occurs in the large strain amplitude region. Under oscillatory shear, we observe several unique behaviors of N1. A negative nonzero mean value of N1 (N1