This study shows the design and implementation of an adaptive one sample ahead preview (AOSAP) control structure tailored for non-sinusoidal permanent magnet synchronous motors (PMSMs), implemented in both d and q coordinates. The control strategy employs a first-order reference model and is systematically compared against conventional Proportional-Integral (PI) controllers. The simulation results in Matlab and the experimental evaluations conducted on a Typhoon hardware-in-the-loop (HIL) 604 platform and a physical prototype demonstrate the superior performance of the proposed AOSAP controller. It exhibits lower tracking errors and faster regulation compared to classical PI controllers. The control algorithms are developed on Texas Instruments Delfino C2000 microcontrollers, showcasing the feasibility of the proposed approach in real world applications.

The periodic output ripple of switching power supplies poses a significant challenge in noise-sensitive, high-precision signal processing circuitry used in high-performance wireless portable equipment. This paper presents an analysis of the impact of an ultra-high-frequency compact buck-type DC-DC converter on the electronic circuitry of portable devices. A class-A amplifier is used as a representative example of the electronic circuitry. We derive equations to analyze the fluctuations in the amplifier's signal output bias voltage caused by the converter's output ripple, allowing for a theoretical examination of the fundamental characteristics of these fluctuations. The output bias fluctuations of the amplifier are calculated using these equations and measured with an evaluation circuit board. The primary method for mitigating these output bias fluctuations is to reduce the converter output noise. Therefore, decreasing the ratio between the natural frequency of the inductor-capacitor (LC) filter and the switching frequency of the converter is effective. This reduction in ratio also facilitates the miniaturization of the converter. When the LC filter of the converter is miniaturized with values of 10 nH and 10 nF, the natural frequency is approximately 16 MHz. By increasing the switching frequency to 1.6 GHz, the fundamental component of the amplifier output bias voltage is suppressed to below 0.3 mV.

In the control system of brushless synchronous starter/generator, accurate information about the field current of MG is the paramount to achieve high dynamic and steady-state performance control. However, the traditional field current estimation (FCE) methods rely on the rotor position, when the position sensor fails, the actual field current cannot be obtained. To eliminate the limitation of rotor position and enhance reliability in field current estimation, a novel rotor position signal-free FCE method is presented. Firstly, the expression of estimated rotor currents of main exciter (ME) is derived and the relationship between the field current and estimated rotor current is analyzed. Then, by extracting the corner points of estimated ME rotor currents. the actual field current can be obtained without rotor position. Finally, the experiment result verifies the feasibility and effectiveness of the proposed method.

Electrochemical energy storage systems function through the cooperative operation of batteries, power converters, and other components. Therefore, methodologies that coordinate electrochemical knowledge with power-system engineering are required to advance the system design and control of such systems. In this paper, a novel physics-based circuit simulation model of a lithium-ion battery is developed as a multi-domain analysis tool. In this model, ion conduction resistance, charge transfer resistance, and open-circuit potential are time-varying elements obtained by coupling a mathematical model to a transmission-line model of a porous electrode to enhance the physical principles in the equivalent circuit model. The model is implemented in a circuit simulator, and the actual measured constant-current charge/discharge curves at rates up to 10C are calculated with high accuracy. We use the circuit simulator to analyze the energy storage system model with a battery pack expanded from this model, a two-quadrant chopper, and a smoothing circuit. On the basis of electrochemical theory, we clarify the effect of the switching operation of the power converter in the system side on the current distribution inside the porous electrode.

Magnetic gears, which can transmit power without mechanical contact, offer lower vibration and acoustic noise compared with conventional mechanical gears. A flux-modulated-type magnetic gear stands out due to its high efficiency and torque density because all the permanent magnets consistently contribute to power transmission. This paper discusses the torque-to-weight ratio improvement and permanent magnet usage reduction of large-scale flux-modulated-type magnetic gears, aiming to construct highly reliable, lightweight, and resource-saving offshore wind power generation systems with magnetic gears. First, to demonstrate the effect of the Halbach array on the torque, an air gap flux density waveform in a prototype magnetic gear with Halbach array magnets is directly measured and compared with that using conventional parallel array magnets. Next, by applying the ideas of the Halbach array and multi-polarization into large-scale magnetic gears, improvements in the torque-to-weight ratio and reductions in permanent magnet usage are demonstrated using the finite element method (FEM).

The occurrence of open-phase faults in five-phase permanent magnet synchronous motors (5Ph-PMSMs) disrupts the current balance among the remaining healthy phases, resulting in the introduction of second and fourth harmonics into the position estimation. To address this challenge, this paper proposes an innovative sensorless control approach specifically for open-phase 5Ph-PMSM systems. This methodology integrates improved second-order generalized integrators (ISOGIs) to effectively mitigate undesirable harmonics and extract the positive sequence component from the distorted back electromotive force (back-EMF). Additionally, an adaptive neutral-voltage compensator is implemented to alleviate the asymmetry present in the back-EMF, thereby further enhancing the precision of the sensorless control. The effectiveness of the proposed methodology is corroborated through rigorous experimental results.

This paper presents the driving modes of a dual-inverter system with a split switch and addresses the voltage imbalance issues that arise during single-inverter mode operation in the overmodulation region. The dual-inverter system serves as the structural foundation; a synchronous pulse width modulation (PWM) technique, specifically applied to the single-inverter mode. In this configuration, structural asymmetries such as unbalanced current return paths and elevated common-mode voltages can reduce the efficiency, electromagnetic interference, and circulating currents. The proposed optimal synchronous PWM strategy, incorporating direct memory access, eliminates the timing jitter during real-time switching events. This approach enables precise voltage vector control and ensures consistent PWM pulse generation, which is particularly important at higher operating speeds. Compared to conventional CPU-based implementations, the proposed method shows enhanced current ripple behavior and harmonic suppression over a wide modulation index range. Simulation and experimental validations demonstrate that the method helps lower harmonic distortion and inverter power loss. Furthermore, by improving waveform symmetry, the technique indirectly aids the suppression of common-mode disturbances. This study offers a practical and scalable PWM control strategy for inverter systems that require high fidelity under real-time constraints and structural sensitivity.

Si reverse-conducting insulated gate bipolar transistors (RC-IGBTs) are important devices for downsizing and cost reduction in automotive inverters. However, because RC-IGBTs integrate IGBTs and free-wheeling diodes (FWDs), the temperature rise during inverter operation becomes significant because both the IGBT and FWD generate losses in a single chip, particularly at higher switching frequencies. Therefore, minimizing the switching losses is essential for enhancing the performance of the RC-IGBTs. This study focuses on Si RC-IGBTs for automotive applications and analyzes active gate control profiles aimed at reducing switching losses by improving the balance between the loss and the surge voltage. This study demonstrated the impact of an enhanced two-level gate current drive profile on the trade-off between switching loss and surge voltage. The results indicated that the proposed profile effectively reduced both the losses and junction temperature in an Si RC-IGBT module during inverter operation, marking a notable improvement in the output performance for the first time.

In 2-phase HB-type stepping motors, since the phase A and B induced voltages contain 3rd and 5th order components, the dq-axis induced voltage contains 4th-order component. Therefore, the dq-axis magnetic flux includes a 4th-order component, and the output torque also includes a 4th-order component. To suppress this torque ripple, conventional methods include ripple suppression using position and acceleration sensors and manual adjustment of the q-axis current commands. However, these methods increase cost, reliability, and labor. Therefore, this paper reports a new method of torque ripple suppression using position and acceleration sensorless control by improving the current response using a resonant controller and generating q-axis current command values using an artificial neural network (ANN), which is a type of AI model. In this paper, we also confirm the effectiveness of suppressing torque ripple in the mid-to high-speed range through actual machine verifications.

The creation of negative energy is key to the development of new space propulsion technologies. It has been believed that it is impossible to generate negative energy using electromagnetic methods. However, we have theoretically demonstrated the existence of a mutual induction circuit that can transiently separate zero energy into positive and negative energy. First, a current is passed through one coil of a mutual induction circuit. Next, the power supply switch is turned off and another switch is turned on to connect the two coils in series. Then, a differential connection is immediately established with another coil to form a closed circuit. At this time, the current increase phenomenon and energy separation phenomenon transiently occur due to the rapid cancellation of the magnetic flux. In the proposed circuit, the amount of positive and negative energy that is transiently separated is equal. Therefore, the law of conservation of energy holds. In this study, we carried out a theoretical analysis to maximize the energy separation efficiency of the proposed circuit and clarified the circuit conditions under which the maximum net efficiency reaches 367%, for example, when the coupling coefficient is 0.992. In addition, we conducted experiments to verify the effectiveness of the theory and simulation. The theoretical and experimental values were in good agreement.

In DC electric railways, lowering the substation output voltage increases the regenerative power but also the loss of traction systems and power feeder circuit. Therefore, the substation output voltage that maximizes the energy conservation effect is determined by a tradeoff between the regenerative brake energies and powering train consumption energy. This study evaluated the energy-saving substation output voltage by applying a method for determining it that focuses on the location dependence of regenerative energy reduction for quadruple track sections and train load conditions. Even in a quadruple track section with rapid trains, the method for determining the substation output voltage can be applied by considering the passing stations, and the voltage can be determined with a few simulations. This study revealed that the impact of the substation output voltage on energy savings for number of feeder circuit is large, and that for train-load conditions is small.

In this study, a leakage inductance calculation method was developed for a magnetic shunt integrated improved core geometry of a power electronic transformer. A magnetic shunt is integrated to increase their leakage inductances to eliminate the need for external inductors in applications such as LLC resonant converters. Four state-of-the-art core geometries (EE, EI, ER and ETD) were studied in this study to determine their advantages and disadvantages in designing a precise leakage inductance. Subsequently, a new improved ERTD core geometry with non-overlapping interleaved winding arrangement was designed, on which shunt integration was performed. Analytic equations were developed using magneto motive force variations and leakage energy distributions for precise calculation of leakage inductance. The thickness of the magnetic shunt and permeability of the shunt material were observed to influence the leakage inductance. A range of leakage inductances was calculated by varying the permeability of the shunt from 100 to 500 and the thickness of the shunt from 0.1 to 0.8 mm. Finite element analysis was performed on a 2 kW, 100 kHz power electronic transformer to verify the leakage inductance calculation method, and the simulated results corresponds with the analytical results.

In this study, a method for developing a cylindrical 6-axis force/torque (F/T) sensor with optimal sensitivity isotropy is proposed. To accommodate diverse conditions, it is desirable for a force sensor to have good isotropy. To evaluate sensitivity isotropy, voltage ratio is introduced as an index corresponding to the ratio of the sensitivity along the z-axis to those along other directions. By analyzing the cylindrical structure using material mechanics, we analytically determined the structure and the location of the gauge attachment point so that the voltage ratio 𝑓 for the force and voltage ratio 𝑔 for the moment would be equal. The maximum nonlinearity and maximum decoupling errors of the developed sensor were 2.40% and 2.23%, respectively. In addition, the average voltage ratios calculated from the measured values were determined to be 𝑓 = 0.873 and 𝑔 = 1.67. This shows that the sensitivity in the z-axis direction toward other axes has been improved compared to previous studies.

A power control method is proposed to improve the energy saving effect of wayside energy storage systems focusing on the power flow control with distant trains. The proposed method controls the filter capacitor voltage of the wayside energy storage system to suppress the fluctuation of the train voltage utilizing a feeder circuit model based on the information of trains and substations. The proposed control method was verified utilizing numerical simulations, confirming the increase of regenerative energy and decrease of substation output energy with respect to the conventional method.

In railway traction systems, optimizing the tangential force acting between the wheels and the rails is crucial for improving transport capacity. The tangential force coefficient fluctuates because of factors such as moisture on the rail surface, resulting in slip phenomena. Various methods for anti-slip control have been proposed in the literature. This study introduces a peak-seeking method to regulate the tangential force in wheel-speed feedback control. With recent advancements in microcontroller performance, the accuracy of tangential force estimation is expected to improve. Therefore, this study proposes a method that employs a disturbance observer to identify the maximum tangential force in locomotive anti-slip control. The design of the observer and peak-seeking gain are analyzed via Bode plots, considering the effects of the calculation cycle. Simulations demonstrate improved tangential force estimation, thereby validating the proposed method.

This paper attempts to separate the AC copper loss, which is significant in high-speed electric motors, into four elements: the skin effect, the in-slot proximity effect, the inter-slot proximity effect, and the effect from permanent magnets. It is found that 84.6% of the AC copper loss in the interior permanent magnet synchronous motor (IPMSM) investigated in this study is caused by the in-slot proximity effect. Furthermore, several countermeasures are presented to reduce the in-slot and inter-slot proximity effects, such as multiple slots, employing finely divided coils, and using aluminum coils. The results demonstrate that the reduction rates of the overall copper losses are 9.0%, 50.1%, and 23.6%, respectively. Furthermore, by combining the three countermeasures, copper loss is finally reduced by 62.5%.

Current source inverters (CSIs) offer advantages over voltage source inverters (VSIs) in drive systems, particularly for motor windings. CSIs feature integrated output capacitors that provide smooth voltages, mitigating issues such as interturn overvoltages, insulation degradation, bearing currents, and electromagnetic interference. Recent advancements in monolithic bidirectional switches have further enhanced their appeal. However, the complexity of CSI modulation and control limits their adoption compared to VSIs, as engineers are more familiar with PWM techniques for VSIs. To address this, we propose the Equivalent DC Machine (E-DCM) concept, wherein the CSI operates in an open loop with a fixed modulation index, allowing direct torque control of the PMSM through the DC link current. This enables the CSI-supplied PMSM to emulate the behavior of a traditional DC machine, simplifying control while avoiding commutation and maintenance issues. The E-DCM concept is validated through transient time-domain simulations, demonstrating its DC machine-like speed-torque characteristics and effective speed control during acceleration from zero to nominal speed.

For dual three-phase permanent magnet motors with yokeless and segmented armature (YASA) topology used for electric aircraft propulsion, reliability is a fundamental requirement. Two fault-tolerant control strategies under single-phase open-circuit faults were analyzed in this study: one based on constant magnetomotive force (MMF) and another based on a reduced-order decoupling mathematical model. Minimization of copper loss and maximization of output torque were set as control objectives. Simulation results demonstrate that the motor speed and torque can be maintained at pre-fault levels through fault-tolerant control. However, the connection of the neutral line introduces significant odd harmonics in the current, causing notable torque ripple. Under the constant MMF-based strategy, torque ripple reached 34.35% and 34.38% for the two control objectives when operating at a 50 Nm load. In contrast, the reduced-order decoupling model-based control strategy alleviated this issue by mathematical correction of the post-fault model of the dual three-phase YASA machine, reducing torque ripple the range of 18.45% - 28.00%.

With the increasing use of electric motors as the primary propulsion system in vehicles, vibrations from the main drive have decreased, making those from auxiliary drives more prominent. As a result, addressing audible noise and vibration in the design of auxiliary motors for automotive applications has become increasingly important. These compact drives, often located near passengers, are more audible compared to the main drive system. Consequently, they may produce vibrations that can excite neighboring structures or components, leading to noise-related concerns. Accurately measuring the structure-borne noise of permanent magnet motors presents a significant challenge. This paper introduces an innovative approach to enhance the precision of vibration measurement and differentiate between electromagnetic and mechanical sources of vibration, making it suitable for vibration measurements in sub-fractional horsepower motors. Furthermore, the proposed measurement methodology provides valuable information on the influence of design variations on vibration characteristics.

This paper presents a fast steady-state analysis method for squirrel-cage induction motors (IMs) based on the time-periodic explicit-error-correction (TP-EEC) method. To reduce the high computational cost associated with conventional time-stepping steady-state analysis of cage IMs, the proposed method extends the dq-TP-EEC framework, originally formulated for three-phase electric machines in a rotational reference frame, to polyphase IMs by incorporating rotor slip frequency. The effectiveness of the proposed method is demonstrated through steady-state analysis of two IM configurations featuring closed and semi-closed rotor slots. Numerical results confirm the method's accuracy and reveal that using smaller time intervals significantly improves convergence in transient analysis when the slip is moderate. Furthermore, this study investigates the method's limitations under conditions of low slip frequency, where a large time constant can affect performance.

The nonlinear friction force is the predominant force disturbance in a permanent-magnet linear synchronous motor (PMLSM) with guide rails and it can affect position control precision, especially during motion reversals (velocity zerocrossing). To minimize the effect of nonlinear friction on position accuracy in the reciprocating motion of a PMLSM, a compensation scheme consists of an iterative learning-based bang-bang compensator (ILBBC) and a generalized proportional-integral observer (GPIO) is presented in this paper. The ILBBC is utilized to compensate for the abrupt change in Coulomb friction force in velocity zero crossing, and the GPIO is added to enhance the compensation performance for the vicious friction force. To effectively merge the ILBBC and GPIO, a three-stage compensation scheme is proposed; thus, the combination of the ILBBC and GPIO is capable of compensating for nonlinear friction in both velocity zero-crossing and non-zero regions. The design and stability of ILBBC and GPIO are theoretically analyzed. Finally, comparative experiments, which include no compensation, GPIO-based compensation, and ILBBC + GPIO compensation, are implemented under two types of sinusoidal position trajectories to demonstrate the effectiveness of the proposed compensation scheme.

Many components in the power grid are developing towards miniaturization. To control the volume and weight of transformers, their working frequency is constantly improving. The influence of high frequency on the distributed parameters of transformers has increased significantly, resulting in voltage distortion, harmonics, and other power quality problems that complicate the internal electromagnetic energy storage. This article analyzes the connection relationship between the topology of stray capacitance parameters and the topology of transformer inductance. Furthermore, a transient model construction method for high frequency transformers under the influence of distorted voltage and harmonics is proposed. The proposed method can describe the response characteristics of transformers under complex operating conditions, such as transient inrush current and the distortion rate of new energy grid connected voltage. The proposed model is suitable for simulation analysis of new hybrid systems.

The Superconducting Maglev (SCMaglev) has adopted a dynamic wireless power transfer (DWPT) system for on-board power supply, with commercial operation set to begin. The DWPT system will be installed along the entire line, and it requires cost-effective maintenance solutions, particularly for the ground-side primary loop. To address this, a condition monitoring system has been developed to measure the induced voltage on the on-board coil and the gap length between the primary loop and on-board coil. This paper comprises four sections. The first section explains the configuration of SCMaglev's DWPT system. The second section presents an estimation method for the induced voltage using existing on-board components and simplified calculation, thereby eliminating the need for and additional sensing coil. The third section describes preliminary verifications of the proposed estimation method. The final section discusses the field verification results from a currently operational line. The filed verifications showed that the estimated voltage closely matched the measured voltage, with differences within several percentage. The measured gap length and on-site investigations indicated that the voltage is influenced by gap length, vehicle motion due to guideway alignment, and localized structural changes. A key achievement of this study is the large-scale verification of the monitoring system on an operational line.

Eddy current braking is an effective emergency braking method for maglev trains; however, the normal forces generated during the braking process can affect the stability of the levitation system of the train. To explore methods for suppressing the normal force, this study employs a nonlinear iterative calculation approach based on the magnetic permeability stratification of the induction plate to analytically compute the normal force of eddy current braking. This approach addresses the challenges in analytical calculations due to the variation in the magnetic permeability of ferromagnetic induction plates owing to magnetic saturation, a problem that traditional subdomain methods are unable to solve. During the calculation process using the subdomain method, the induction plate is divided into N layers of equal thickness and an iterative calculation method is employed to determine the magnetic permeability of each layer, thereby improving the computational accuracy. Subsequently, a finite element simulation is used to verify the analytical calculation results. The influence of various parameters on the normal force is analyzed. Aiming at the demand for emergency braking for high-speed maglev, the parameters are optimized to suppress the normal force.

In this study, the loss of a permanent magnet synchronous motor (PMSM) with a ductile iron frame is evaluated. First, the magnetic and electrical properties of the ductile iron FCD400 that was used for the frame were measured. Subsequently, the measured properties were applied to the loss analysis of the PMSM with the ductile iron frame. The results of the analysis demonstrate that significantly large losses are generated in the frame when the stator core is highly saturated. In addition, the effect of carrier harmonics on the generated frame loss was examined. As a result, the frame loss is mainly generated by the fundamental component included in the pulse-width modulation voltage waveform, and the contribution of the carrier harmonics is negligibly small. Finally, the effect of the presence of the frame on the torque performance at low-speed and high-torque conditions is discussed.

This article proposes an indirect vector control for induction motor control in electric vehicle propulsion systems. Torque ripple suppression and improvement of the transient torque response are the key challenges. Therefore, the predictive controller was applied to the current control loop of an indirect vector control. To achieve fast transient response and small torque ripple, this study focused on the performance of the current control loop. A mathematical model of the electric vehicle propulsion system consisting of the mechanic of the electric vehicle load, battery, inverter, and three-phase induction motor is proposed. The accuracy of the model was validated and confirmed using the MATLAB/Simulink program. The hardware-in-the-loop technique was implemented to confirm the fast and accurate current performance for the electric vehicle system. The testing results demonstrated that an indirect vector control based on the predictive controller provided a faster transient current response and less current ripple than the PI controller. As a result, a good transient torque response and small torque ripple were achieved by the predictive controller under changing speed conditions.

Low-noise switching controls have been proposed for a power converter circuit. However, the noise reduction effect is strongly influenced by measurement conditions. This paper focuses on the relationship between the noise reduction effects and measurement conditions in the low-noise switching control for power conversion circuits and proposes a control that combines the variable-frequency and phase shift control. This paper presents the mechanism of influence of measurement conditions such as detection mode and resolution bandwidth on low-noise switching controls. A specific condition that makes noise reduction challenging is shown. Even under conditions where noise reduction is difficult, the proposed control can reduce noise at approximately 500 kHz by 6 dB. The parameters for switching waveforms are determined via theoretical calculations. The results of measurements conducted using a buck converter agree with the theoretical results. Additionally, for suppressing ripple current, the relationship between ripple current and parameters for switching waveforms is evaluated. This control enables the selection of parameters that can result in both noise reduction and ripple current suppression.

Traditional strategies for controlling the DC bus voltage of a photovoltaic grid-connected inverter cause large fluctuations in DC bus voltage and affect the stability of the system under various uncertain disturbance factors, such as time-varying disturbances and parameter perturbations. To solve this problem, an improved linear active disturbance rejection control (LADRC) strategy is proposed. First, the active power disturbance and the dual-loop control structure of the photovoltaic grid-connected inverter is described and the DC bus is dynamically modeled, second, the traditional LADRC is designed and, based on the traditional extended state observer (ESO) , the cascade ESO structure is used to improve the disturbance estimation suppression capability, Finally, the anti-disturbance and tracking terms in the cascade ESO are decoupled, which simplifies the controller parameter setting and further improves the anti-disturbance performance of the system. Theoretical analysis, simulation results, and hardware-in-the-loop experiments are used to verify the effectiveness and feasibility of the proposed strategy.

This paper proposed a novel rotor structure for V-shaped interior permanent magnet motors (IPM motors) to reduce the magnet volume. Although the magnet volume, required to obtain the desired torque, could be reduced using a V-shaped magnet arrangement, its effectiveness was limited due to the leakage flux pathing through the central bridge. In the proposed motor, the central bridge was replaced by a nonmagnetic wedge, and the leakage flux path was completely eliminated. For this reason, the magnet reduction effect of the concentrated flux structure in the V-shaped IPM could be maximized, and the magnet volume could be reduced compared with that of conventional motors. To validate its effectiveness, numerical and experimental verifications were conducted. Moreover, the obtained results were compared with those of conventional motors.

This paper introduces novel magnetic slot wedges made of a newly developed resin-free magnetic composite material. The novel magnetic slot wedges exhibit superior permeability and strength compared with conventional magnetic slot wedges made of iron powder and resin. Finite Element Method (FEM) analysis indicated that the efficiency improvement of a 7.5 kW 2-pole induction motor with the novel magnetic slot wedges was expected to be approximately 1.5 times higher compared to that with the conventional magnetic wedges. Installing those magnetic slot wedges into the originally vacant slot openings of commercially available 7.5 kW 2-pole, 7.5 kW 4-pole, and 0.75 kW 6-pole induction motors resulted in efficiency improvements of 1.6%, 1.1%, and 2.8%, respectively, at each rated output. Noticeable decreased in temperature rise were also observed. Consequently, the novel magnetic slot wedges proved to be effective in improving the efficiency of induction motors without requiring significant design changes, such as increasing the motor size.

To realize a decarbonized world, high efficiency in industrial electric motors, including large-sized motors in the range of several hundred kW, is required. Permanent magnet motors are the most efficient for this purpose. However, their adoption in large-sized motors can be challenging owing to the scarcity and cost of rare earth materials. Owing to this, synchronous reluctance motors (SynRMs) are gaining attention. They do not use permanent magnets in the rotor and are more efficient than the widely used induction motors. However, to determine the operating characteristics of SynRMs, an actual load test is necessary. For large-sized SynRMs over in the range of several hundred kW, conducting this test is expected to be challenging owing to the requirement of large test facilities. This paper proposes a method to examine the operating characteristics of SynRMs using a standalone test and reports the evaluation results of the proposed testing method. This method provides a practical solution for evaluating the performance of large-sized SynRMs, potentially facilitating their wide adoption in industrial applications.

This paper presents a coupled analysis method for vibration energy harvesters based on predictor-corrector approach. To consider the coupling of vibration and electromagnetic systems, time-evolutions of system states are predicted, and coupling factors are evaluated from the predicted states. Then, the next system states are evaluated by solving the system's governing equations. The coupling factors are corrected using the predicted and computed states. It is shown that the proposed method can evaluate the performance of a vibration energy harvester with little computational burden, while the analysis results almost equal those of the conventional quasi-strong coupled analysis method. Moreover, the measurement results show that the proposed method can qualitatively simulate the behaviors of nonlinear vibration energy harvesters.

In industrial applications that require low-cost positioning and high torque, stator permanent magnet hybrid stepper motors (SPMHSMs) possess significant application potential. The torque of the SPMHSM is related to the number of teeth per stator pole. However, few studies have analyzed the effect of the number of stator teeth on motor performance. To this end, in this study, we designed SPMHSMs with four, five and six-tooth configurations. First, the topology of the SPMHSM is introduced and its operating principle is analyzed. Next, the three motors are designed with the same PM and electrical load. Lastly, we analyzed the electromagnetic performance of these three motors in terms of several factors including magnetic flux distribution, back electromotive force, detent torque, and output torque. The obtained results show that the output torque of the SPMHSMs with five and six-tooth configurations is 2.61% and 3.26% higher than that of the SPMHSM with four-tooth configuration, whereas that with a four-tooth configuration has a wilder torque-current range.