Eiji Hiraki

Learn More
In this paper, the practical impedance approach steady-state analysis in the frequency domain for the three-phase self-excited induction generator (SEIG) with squirrel-cage rotor is presented along with its operating performance evaluations. The three-phase SEIG is driven by a variable-speed prime mover(VSPM) in addition to a constant-speed prime mover(More)
In this paper, we propose a smart charger for electric vehicles with a power-quality compensator. The proposed smart charger consists of four-leg insulated-gate bipolar transistors (IGBTs). Three legs are used for a single-phase full-bridge-based pulsewidth-modulated (PWM) rectifier, which converts power from ac to dc during the battery-charging operation(More)
Wide-bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) are promising materials for next-generation power devices. We have fabricated a normally on GaN-based high-electron-mobility transistor (GaN HEMT) for power electronic converters. In this paper, the current collapse phenomena, which are distinctive characteristics of GaN(More)
This paper is mainly concerned with a high frequency soft-switching PWM inverter suitable for consumer induction heating system. Proposed system is composed of soft switching chopper based voltage boost PFC input stage and phase shifted PWM controlled full bridge ZCZVS high frequency inverter stage. Its fundamentals of operating performances are illustrated(More)
This paper presents a bidirectional DC-DC converter suitable for low-voltage super capacitor-based electric energy storage systems. The DC-DC converter presented here consists of a full-bridge circuit and a current-fed push-pull circuit with a high frequency (HF) transformer-link. In order to reduce the device-conduction losses due to the large current of(More)
This paper presents a zero-voltage and zero-current soft-switching (ZVZCS) PWM three phase inverter with a single auxiliary resonant commutation cell. All of the main switches in the three-phase inverter side can be turned on and turned off under zero-voltage and zero-current condition. The operating principle of proposed commutation cell is described, and(More)
In this paper, we propose a new control algorithm to reduce the capacity of a previously proposed smart charger for electric vehicles (EVs) on single-phase three-wire distribution feeders with reactive power control. The basic principle of the proposed control algorithm is discussed in detail. It is shown that controlling the reactive power on the source(More)
In this paper, we propose the control method of a peak shaving system for an electric injection molding machine (EIMM). The peak power shaver consists of a multiphase bidirectional dc-dc converter and supercapacitors (SCs), and is connected to a dc link of the inverter fed injection motor drive system of the EIMM. In the proposed control method, electric(More)
In tandem with the penetration of PHV as well as EV, contact-less power supply system in parking towers have become important subjects. In parking towers, EV and PHV are charged on the traveling pallets, supply power is to be transmitted from the building to travelling pallets. In this paper, high-frequency link AC-AC converter for contact-less power supply(More)
This paper proposes a novel analysis method for the dual transmitting resonators wireless power transfer (DTR-WPT) system. The DTR-WPT is attractive for its higher efficiency and greater power transfer capability compared with the conventional single transmitting resonator wireless power transfer (STR-WPT) system. However, analytical understanding of the(More)