Shigeyuki Funabiki

A new buck-boost-operation-based sinusoidal inverter circuit

This paper proposes a novel sinusoidal inverter circuit. The performance of this inverter circuit is based on buck-boost operation, as it is well known in a DC chopper circuit. The proposed inverter has a distinguished feature of step-up and step-down output voltage. The sinusoidal output voltage of the inverter is obtained by using a hysteresis-comparator scheme. The behavior of the inverter circuit is described in detail based on the switching conditions and operation modes. The computer simulation is carried out in order to confirm the performance and advantage of the proposed sinusoidal inverter.

A method of compensating harmonic currents generated by consumer electronic equipment using the correlation function

This paper proposes a novel method of compensating harmonic currents generated by consumer electronic equipment that act as harmonic voltage sources, using the correlation function. The distribution transformer is equipped with an additional winding on the secondary side, and a single-phase voltage-source pulse-width-modulated (PWM) inverter is connected to the added winding, acting as a shunt-active filter. The leakage inductor of the added winding behaves as though connected in series to the leakage inductor on the secondary side winding connected to the consumer electronic equipment. The shunt-active filter can thus be used to compensate harmonic currents on the source side without an inductor series-connected to the harmonic voltage source. The basic principle of the proposed compensation method is discussed in detail. Digital computer simulation is implemented to demonstrate the validity and practicability of the proposed compensation method using the proposed harmonic current detection method using the correlation function.

A new approach to the capacitor-commutated converter for HVDC-a combined commutation-capacitor of active and passive capacitors

This paper introduces a new approach to the capacitor-commutated converter (CCC) for HVDC. A small-rated three-phase voltage-source PWM converter is connected between a series commutation capacitor and thyristor rectifier through matching transformers. The PWM converter acts as auxiliary commutation-capacitor for the thyristor rectifier while the series capacitor acts as the main commutation capacitor. The capacitance, which is the sum of the small-rated active and series passive capacitors, is variable, so that stable commutation is obtained. In CCCs commutation failure occurs when the AC bus voltage is recovered whereas the proposed combined commutation-capacitor can achieve successful commutation for both rapidly decreasing and increasing AC bus voltages. The basic principle of the proposed active-passive capacitor commutated converter is discussed in detail. Then, constant margin-angle control with a constant firing angle of the thyristor converter is proposed using a function generator block. Digital simulation demonstrates the novelty and effectiveness of the proposed active-passive capacitor commutated converter.

A new method of damping harmonic resonance at the DC link in large-capacity rectifier-inverter systems using a novel regenerating scheme

This paper proposes a new method of damping harmonic resonance at the DC-link of a large capacity rectifier-inverter system such as in rapid-transit railways. A voltage-source PWM converter is connected in series to the DC capacitor of the rectifier through a matching transformer, acting as a damping resistor to the DC capacitor current. No filters are needed to extract harmonic components from the DC capacitor current. This results in a quick response and highly stable damping. The required rating of the PWM converter is less than one-thousandth of that previously proposed. The basic principle of the proposed damping method is discussed in detail, then confirmed using digital computer simulation. Experimental results verify the validity and practicability of the proposed damping method.

An experiment of fuzzy control for leveling load power fluctuations using an SMES simulator

Leveling of load power fluctuations and compensation of reactive power can be achieved by a superconducting magnetic energy storage (SMES) installed close to the consumer end in a power system. This reduces transmission losses and lowers the required ratings of equipment in the power system while improving power system stability. An SMES simulator based on power electronics technology, i.e. a power converter, is proposed. An experiment to level load power fluctuations with the SMES simulator is put into practice to verify the proposed fuzzy control strategy. Experimental results agree well with simulation results. Estimating indexes show that ratings and power loss are half of those without the SMES power control system. The presented power control system based on fuzzy control strategy is proved useful for leveling load power fluctuations.

A monocular vision-based position sensor using neural networks for automated vehicle following

This paper presents a new position sensor with a CCD camera based on neural networks that measures the distance and direction angle to and the pose angle of the lead vehicle in automated vehicle following. A picture image of lamps mounted on the lead vehicle is obtained with the CCD camera. Lamp positions are established in a rectangular coordinate system by means of graphic data processing. The measuring process of the proposed position sensor is developed by neural network learning with backpropagation. The number of lamps can be reduced from four to three without sacrificing sensor accuracy. This reduction in the number of lamps shortens acquisition time in graphic data processing. Experimental results show that the distance, direction angle and pose angle are sufficiently accurate for practical use in automated vehicle following.

A new method of damping harmonic resonance at the DC-link of a large-capacity rectifier-inverter system

This paper proposes a new method of damping harmonic resonance at the DC-link of a large-capacity rectifier-inverter system such as in rapid-transit railways. A voltage-source PWM converter is connected in series to the DC capacitor of the rectifier through a matching transformer, acting as a damping resistor to the DC capacitor current. No filters are needed to extract harmonic components from the DC capacitor current. This system is thus highly stable and the required rating of the PWM converter is less than one-thousandth of that previously proposed. The basic principle of the proposed damping method is discussed in detail, then confirmed using digital computer simulation. The simulation results demonstrate the excellent practicability of the proposed damping method.

A novel harmonic compensator for consumer electronic equipment using the correlation function

This paper proposes a novel harmonic compensator for consumer electronic equipment that act as harmonic voltage sources, using the correlation function. The distribution transformer is equipped with an additional winding on the secondary side, and a single-phase voltage-source PWM inverter is connected to the added winding, acting as a shunt active filter. The leakage inductor in the secondary side winding, which is connected to the consumer electronic equipment, behaves as though connected in series to the consumer electronic equipment. The shunt active filter can thus be used to compensate harmonic currents on the source side without an inductor series-connected to the harmonic voltage source. The basic principle of the proposed compensation method is discussed in detail, then confirmed using digital computer simulation. Experimental results demonstrate the validity and practicability of the proposed compensation method using the correlation function.

A novel method of compensating harmonic currents generated by consumer electronic equipment based on the correlation function

This paper proposes a novel method of compensating harmonic currents generated by consumer electronic equipment that act as harmonic voltage sources, using the correlation function. The distribution transformer is equipped with an additional winding on the secondary side, and a single-phase voltage-source PWM inverter is connected to the added winding, acting as a shunt active filter. The leakage inductor of the added winding behaves as though connected in series to the leakage inductor on the secondary side winding connected to the consumer electronic equipment. The shunt active filter can thus be used to compensate harmonic currents on the source side without an inductor series-connected to the harmonic voltage source. The basic principle of the proposed compensation method is discussed in detail. Digital computer simulation is implemented to demonstrate the validity and practicability of the proposed compensation method using the proposed harmonic current detection method based on the correlation function.

High Efficiency Low Noise SMPS System - Single Phase PFC Rectifier Side

Improvement of single phase PFC rectifier side in SMPS system is discussed in this paper. A novel single phase recovery-less PFC rectifier which have only additional one power diode compared with the conventional single phase PFC rectifier is presented in this discussion for high efficiency low noise SMPS system. Its circuit operation of the proposed single phase recovery-less PFC rectifier is described and discussed on the bases of experimental results.