This paper proposes a permanent-magnet (PM) machine position-sensorless drive for high speed (> 10-kr/min) applications. A discrete-time back electromotive force (EMF) voltage estimation method is ...developed to overcome several high-speed position sensing issues, including the voltage error due to the digital-to-analog conversion, inductive cross-coupling, and deviation between the estimated EMF and actual EMF resulting from the digital implementation. To overcome these problems, an observer-based EMF estimation is proposed with three implementation considerations. They are 1) a discrete-time dq current observer to remove the inductive cross-coupling effect for the EMF estimation, 2) a delay model to compensate the voltage error, and 3) a discretized model to estimate the sampled EMF in the discrete-time. A high-speed PM machine is experimentally evaluated to verify all proposed sensorless drive methods.
Abstract A fault-tolerant vernier permanent magnet machine (FTVPMM) with five phases for direct-drive occasions is designed and analyzed. The construction of the proposed FTVPMM is introduced and the ...principle of the vernier modulation effect is investigated. Parameters are designed and optimized by finite element analysis (FEA), including tooth width, slot opening, PM thickness, pole-arc coefficient, air-gap length, and rotor yoke. Furthermore, major electromagnetic performances are discussed, including cogging torque, no-load back electromotive force (BEMF), output torque, and fault-tolerant capability.
Abstract
Two new five-phase out-rotor inner-stator permanent magnet (PM) vernier machines (PMVM) with different PM arrays are proposed to investigate the performance compared with an existing PMVM. ...The Halbach arrays and consequent arrays are adopted to enhance torque density. Also, the operation principle of PMVM is discussed by an analytical method. Moreover, some parameters are optimized to achieve better performance. Finally, performance such as back electromotive force, torque, loss, and efficiency are discussed by the finite element method.
In this paper, we define a new different model for Heisenberg velocity microfluidic mKdV electromotive forces. Also, we construct some relations for ferromagnetic Heisenberg velocity microfluidic ...mKdV magnetic flux density. We design ferromagnetic Heisenberg velocity microfluidic optical mKdV flux domain representation. Finally, we obtain Heisenberg velocity microfluidic mKdV flux density.
In this study, a torque enhancement principle for a stator permanent-magnet (PM) Vernier machine with a consequent pole structure is proposed. The novelty of the manuscript is the explanation of how ...stator PM Vernier machines benefit from consequent pole structure. Although a similar concept of stator PM Vernier machines with a consequent pole structure has been investigated in previous studies, a clear torque enhancement principle was absent. The keys to torque enhancement are the decrement of nonworking harmonics and increment of working harmonics. To demonstrate these phenomena, the torque contributions from the harmonics were calculated. Subsequently, the performances of the conventional machine and consequent pole machine were compared to verify the enhancement principle. The electromagnetic performances, including the back electromotive force and torque, were compared. The results show that the stator PM Vernier machine benefits significantly from torque enhancement using the consequent pole structure, and the torque enhancement principle was verified.
In order to improve the performance of the high-speed brushless direct current motor drives, a novel high-precision sensorless drive has been developed. It is well known that the inevitable voltage ...pulses, which are generated during the commutation periods, will impact the rotor position detecting accuracy, and further impact the performance of the overall sensorless drive, especially in the higher speed range or under the heavier load conditions. For this reason, the active compensation method based on the virtual third harmonic back electromotive force incorporating the SFF-SOGI-PLL (synchronic-frequency filter incorporating the second-order generalized integrator based phase-locked loop) is proposed to precise detect the commutation points for sensorless drive. An experimental driveline system used for testing the electrical performance of the developed magnetically suspended motor is built. The mathematical analysis and the comparable experimental results have been shown to validate the effectiveness of the proposed sensorless drive algorithm.
In this article, a sensorless field-oriented vector control strategy combined with an improved adaptive sliding mode observer and a back electromotive force (back EMF) observer is presented for a ...surface permanent magnet synchronous motor. First, based on a sliding mode, a current adaptive observer with estimation of back EMF is proposed to obtain the error of the back EMF, which can reduce system chattering. Then, a back EMF observer based on the back EMF error is constructed to adaptively track the rotor speed and position, which avoids complicated computation. Moreover, the stability of two observers is proved by using the Lyapunov stability theory. Finally, some simulations and experiments are given to show that the proposed method can track the changes of rotor speed and position with good characters, such as fast convergence, little chattering, and good robustness.
Abstract
This paper discussed the performance changes under a rated operation state and permanent magnet loss-of-field fault of a 5KW permanent magnet synchronous motor (PMSM) in a 200 mm shaftless ...rimless thruster. These changes in key parameters include air gap flux density, back electromotive force, output torque, current and magnetic field. Using the changes in these parameters to analyze the running state of the motor provides a reference for the early fault diagnosis of a permanent magnet synchronous motor at the simulation level.
Abstract
This paper proposes angular velocity vector feedback speed control system, the amplitude and phase signals of diagonal velocity are extracted, and signals are converted into current and ...voltage vector signals to achieve high efficiency and speed precision. Brushless motor rotational stability on speed and torque are classified, comparative characteristics analysis of dynamic speed and torque between conventional method and proposed method are simulated, results consisting of speed accuracy, the waveform of stator current and back electromotive force of each phase are all compared and analyzed, verifying fitness and validation of the proposed method.
