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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 power is stored in the SCs through the multiphase bidirectional dc–dc converter with a pulsewidth-modulation rectifier while the injection motor is at rest. When the injection motor is accelerating, the stored power in the SCs together with the power from the distribution feeders is supplied to the injection motor. Thus, the peak power can be shaved. The basic principle of the proposed control method is discussed in detail, then confirmed by digital computer simulation and experimental setup. The simulation and experimental results demonstrate that the peak power is shaved by 70% using the peak power shaving system. [ABSTRACT FROM PUBLISHER]

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 or from dc to ac during the battery-discharging operation. This PWM rectifier can compensate reactive and unbalanced active currents on single-phase three-wire distribution systems because the third leg is connected to the neutral line of single-phase three-wire distribution feeders. The fourth leg is used as a bidirectional dc–dc converter for battery-charging and battery-discharging operations. The three-leg PWM rectifier uses only constant dc-capacitor voltage control, which is commonly used in active power line conditioners. Thus, the authors have developed the simplest possible control method for a single-phase power-quality compensator. The basic principle of the proposed smart charger is discussed in detail and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results demonstrate that balanced source currents are obtained on the secondary side of the pole-mounted distribution transformer for battery-charging and battery-discharging operations. [ABSTRACT FROM PUBLISHER]

This paper proposes a new topology for a current balancer with half-bridge inverters in single-phase three-wire distribution systems. Two half-bridge inverters are connected to the sources. The midpoint of the two capacitors on the DC-side is connected to a neutral line. The two half-bridge inverters function as a current balancer for single-phase three-wire distribution systems by exchanging the active and reactive power on each feeder through the two DC capacitors. The third leg functions as a DC-capacitor-voltage balancer for two DC capacitors connected to the half-bridge inverters. Thus, balanced source voltages and currents are obtained on the secondary side on the pole- mounted distribution transformer with balanced DC-capacitor voltages. The basic principle of the proposed current balancer is discussed in detail, and then confirmed by digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental results show that balanced source voltages and currents are obtained on the secondary side on the pole-mounted distribution transformer with balanced DC-capacitor voltages. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(4): 38-46, 2012; Published online in Wiley Online Library (). DOI 10.1002/eej.22277 [ABSTRACT FROM AUTHOR]