This paper describes a stability analysis of single-phase sinusoidal current input converter without sinusoidal standard source voltage waveform. First, the pulse width modulation (PWM) operation model of sinusoidal current input converter was constructed. Then, the PWM operation model was analyzed with discrete time quaternization and z conversion. The analysis formulated the PWM period limit. Based on the analysis formulation, it was clarified that the stability limit of PWM frequency and the reactance value of the power supply reactor are inversely proportional. This implies that when the reactance value decreases due to the miniaturization of the power supply reactor, it is necessary to set the PWM frequency higher. The effectiveness of the PWM period limit was confirmed via simulation and actual circuit tests. As test conditions, the reactance value and PWM frequency of the power supply reactor are changed. The test results show the vibration of the power supply current waveform and the results of the current harmonics before and after the stability limit.

This study proposes phase-delay compensation for time delay in flux-based phase-manipulated damping control. The proposed method compensates for controller delay by applying a coordinate transformation to the flux vector. This method was experimentally verified using an electric-vehicle motor. Moreover, the proposed method improves the maximum frequency by suppressing vibration caused by motor resonance.

Wireless power transfer (WPT) systems for moving electric vehicles or railways have been frequently addressed in recent studies. WPT technology is also used to supply on-board power in SCMaglev systems. In this study, we evaluated a power control method for the secondary converter used in the SCMaglev WPT system. The characteristics of the proposed method were validated through both simulation and experiments using a test facility. With this approach, a power factor of 0.97 or higher was achieved in stationary system experiments.

In this study, we propose a diesel generator system using a permanent magnet synchronous machine and voltage multiplier circuit for application in diesel electric and hybrid vehicles. In the voltage multiplier circuit, capacitors inserted between full-bridge rectifiers and the permanent magnet synchronous machine act as phase-shift capacitors for enhanced power generation and potential isolation capacitors for voltage multiplication. The proposed system has the advantage of being able to achieve a high DC voltage even when the voltage output by the generator is low. In this paper, we outline the proposed system, and reports on the results of theoretical analysis to design a power generation system for a diesel electric railcar. We also report on simulation-based operational verification.

An important issue in permanent-magnet synchronous motors (PMSMs) for electric vehicle (EV) traction is estimating the temperature of the rotor permanent-magnet in real-time. This paper proposes a novel rotor flux-amplitude estimation method to enable real-time rotor magnet temperature estimation of the PMSM without flux dq-cross coupling. The proposed method has the following features: (a) A minimum-order D-flux state observer, included in the D-filter, is used for the real-time estimation of the rotor flux-amplitude. (b) The d- and q-inductances required by the observer are estimated using an adaptive parameter identifier. (c) The adverse effects caused by the current detection offset on the flux-amplitude estimate and identified inductances are overcome by utilizing the characteristics unique to each system. (d) The instability caused by the coupling of two real-time systems is addressed by adopting a special structure that prevents such instability. (e) Using the proposed method, the real value of the rotor flux-amplitude can be estimated in 0.9s after the zero initial-state start.

In this study, we verify the errors in sensorless magnet temperature estimation by using the induced voltage of interior permanent magnet synchronous motor and applying electromagnetic field analysis. The method considered for reducing the errors verified the effect of current and magnet temperature on inductance in the motor. As a result, the estimation errors were reduced from a maximum of 33°C to 0.4°C or less.

This article introduces the Advanced Power Supply System Laboratory (PI: Assoc. Prof. Katsuhiro Hata) at the College of Engineering, Shibaura Institute of Technology. The laboratory focuses on Wireless Power Transfer (WPT), DC-DC converters, Active Gate Drive (AGD), and e-mobility.