This paper proposes a high-frequency injection (HFI) based dq-inductance estimation technique for synchronous machines. The d and q-axes inductance are estimated using a single HF injection between dq-axes, i.e., 45' injection angle. The d and q-axes incremental inductance variation over four quadrants dq-plane operating condition is evaluated. The proposed technique can operate in real-time without a controlled position or velocity from the load side. No previous knowledge of machine parameters nor computationally expensive regression processes are required. The proposed technique can be used to evaluate the sensitivity of inductive-saliency based self-sensing to determine preferable self-sensing operating conditions for permanent magnet synchronous machines (PMSMs).

Torque measurement/estimation in surface permanent magnet synchronous machines (SPMSMs) is needed in many applications. Torque measurement systems are expensive, require extra room, add weight, can introduce resonances into the system, and their performance can be compromised due to electromagnetic interference. Alternatively, torque can be estimated, accurate knowledge of machine parameters being critical in this case. Injection of a high frequency (HF) signal in the stator via inverter has been shown to be a viable option for online identification of machine parameters identification required by torque estimation methods for interior PMSMs (IPMSMs). However, the reported methods require the use of two pulsating HF currents, which introduces concerns both on the adverse effects on machine's performance (additional noise, vibration, additional, …) as well as to the additional computational burden, as HF current controllers are required. This paper proposes a torque estimation method for SPMSMs using a single HF signal; further more, a HF voltage signal can be used, avoiding the use of HF current controllers, and therefore simplifying the implementation.

Torque measurement/estimation in permanent magnet synchronous machines (PMSMs) is required in a large variety of applications. Direct torque measurement by means of torque transducers is typically limited to laboratory applications due to cost, reliability, and room concerns. Alternatively, torque can be estimated. Torque estimation methods require accurate knowledge of machine parameters. Injection of a high frequency (HF) signal in the stator via inverter has been shown to be a viable option for online machine parameters identification in PMSMs. However, this introduces concerns on the performance of the machine due to the noise, vibration, and additional losses produced by the HF signal. This article proposes a torque estimation method for PMSMs using low cost Hall-effect sensors. The method is based on the dependency of the leakage flux complex vector due to interaction between permanent magnet flux and stator coil flux and does not interfere with the drive operation of the machine.

Power system disruptions can be categorized as issues with the quality of electricity brought on by voltage sags, lightning strikes, and other system-related interferences. The static transfer switch (STS) has recently emerged as the most important technology for electric power transmission, distribution, and control systems to manage power supply during power system disruption issues, particularly in cost-effectively supplying power to critical loads and sensitive loads without interruption. In this paper, for the switching between the two AC sources during the voltage disruptions issue with low transfer time, a smart static transfer switch (SSTS) based on a digital switching algorithm and Triac semiconductor switch is proposed and experimentally tested. A digital switching algorithm based on online AC voltage sensing and zero-crossing detection is proposed and implemented inside a DSP MCU. The printed circuit board (PCB) of the proposed SSTS is designed and manufactured for the experimental performance investigation with different AC input voltage conditions. A comparative study based on the advantages and disadvantages of the proposed SSTS system with the previous works is also presented. A smart static transfer switch with a transition time of less than one cycle and a digital protection technique during fault conditions is obtained in this work.

The efficient design optimization of electric machines for electric power steering (EPS) applications poses challenges in meeting demanding performance criteria, including high power density, efficiency, and low vibration. Traditional optimization approaches often fail to find a global solution or suffer from excessive computation time. In response to the limitations of traditional approaches, this paper introduces a novel methodology by incorporating a Gaussian process-based adaptive sampling technique into a surrogate-assisted optimization process using a metaheuristic algorithm. Validation on a 72-slot/8-pole interior permanent magnet (IPM) machine demonstrates the superiority of the proposed approach, showcasing improved exploitation–exploration balance, faster convergence, and enhanced repeatability compared to conventional optimization methods. The proposed design process is then applied to two surface PM (SPM) machine configurations with 9-slot/6-pole and 12-slot/10-pole combinations for EPS applications. The results indicate that the 12-slot/10-pole SPM design surpasses the alternative design in torque density, efficiency, cogging torque, torque ripple, and manufacturability.

The second-order generalized integrator based orthogonal signal generator (SOGI-OSG) is commonly used to produce direct and quadrature axis ( dq-axes) signals in stationary reference frame for single-phase systems. Fast and robust OSG with harmonic rejection capability is required for parallel operation of power generation systems. The frequency response function (FRF) of classical OSG does not show robustness towards DC offset and grid harmonic disturbances compared to the direct signal of SOGI. This paper presents OSGs based on n ^th order bandpass filter with a phase shifter using a scaled Q factor as a design variable. The frequency and time-domain performance analysis will be performed based on the scaled Q factor to simplify the design process of the proposed OSGs. The -3dB frequency and settling step time will be matched in higher order OSGs selecting a scaled Q factor. The proposed method will show enhanced harmonic rejection ratio of an additional -20dB with increasing OSG order with tradeoff in computational burden.