Katsuji Iida

The influence of the conducting inductance in the auxiliary resonant commutated pole inverter

The auxiliary resonant commutated pole (ARCP) inverter is well-known by its small EMI and switching loss. However, in the high voltage-high power application, there exist some problems such as the difficulty of the complete ZVS realization, influence of the conducting inductance and so forth. In this paper, the characteristics of the ARCP inverter are analysed, with consideration of the conducting inductance influence. The useful analytical results are obtained and confirmed by the experiment.

High power soft switching PWM AC auxiliary power supply system of the electric railway rolling stock and its deadbeat control

This paper presents a novel high power auxiliary three phase AC power supply system of the electric railway rolling stock. In this power supply system, an Improved auxiliary resonant commutated pole (ARCP) inverter with newly developed switches and a new deadbeat control technique are used to realize high performance such as small size, light weight, low acoustic noise, fast response, low EMI and so forth. Also, a design-oriented analysis of the proposed deadbeat control technique is presented.<<ETX>>

An improved gate drive circuit using an air core reactor developed for high power GTO thyristors

An improved gate drive circuit for high power GTO thyristors is presented. The energy storage/transfer characteristics of an air core reactor and the fast switching characteristics of FETs are employed to make the high gate current of sharp pulse form. The power loss in the gate drive circuit can be reduced by using the low resistance and the hysteresis comparator to detect and control the steady on-gate current. The proposed gate drive circuit is analyzed, and its usefulness is confirmed by experiments.<<ETX>>

Analysis of the improved soft-commutated PWM inverter by using an AC current transformer

In the high power DC-DC converter and DC-AC inverter, the soft-commutated PWM technique has been receiving much attention from the viewpoints of decreasing the switching noise, reducing the switching power loss in the main power switch and removing the complicated snubber circuit and so forth. However, the conventional soft-commutated PWM converter and inverter have some defects such as high voltage and/or high current stresses on the switches, the necessity of the additional switches for realizing soft-commutation, and the relatively large power loss caused by the large circulating current composed of the load and resonant ones. This paper presents an improved half-bridge type soft-commutated PWM inverter, in which an AC current transformer and an additional resonant capacitor are employed to realize the soft-commutated PWM operation of the switches and to decrease the circulating current. Consequently, in the proposed circuit. the power loss caused by this circulating current is sufficiently reduced. The operation performance characteristics of this soft-commutated PWM inverter are analyzed.<<ETX>>

New soft-commutated PWM inverter with AC current transformer

The soft-commutated PWM inverter is very attractive for high power applications. In the conventional soft-commutated PWM inverter, however, there exist some deteriorative problems such as high voltage and/or high current stresses on the switches, the necessity of the additional switches for realizing soft-commutated PWM, and the relatively large power loss caused by the large circulating current composed of the load current and the resonant current. This paper presents a new soft-commutated PWM inverter, in which an AC current transformer and a main resonant capacitor are used to detect the value and the polarity of the AC load current, and to realize the soft-commutation of the switches without causing the above deteriorative problems. The operation and the characteristics of this soft-commutated PWM inverter are analyzed and its usefulness is confirmed by experiments.<<ETX>>

An Improved Gate Drive Circuit Using an Air Core Reactor Developed for High Power GTO Thyristors

This paper presents an improved gate drive circuit for high power GTO thyristors. The energy-storage/transfer characteristics of an air-core reactor and the fast switching characteristics of FET are employed to make a high gate current of sharp pulse form. The power loss in the gate drive circuit is reduced by using the low resistance and the hysteresis comparator to detect and control the steady on-gate current. The proposed gate drive circuit is analyzed and its usefulness is confirmed by experiments.

An active driving circuit for high-voltage high-power SI-thyristor

The high-voltage, high-power SI-Thyristor (SI-Thy) is developed and is being produced to be applied in many power electronics applications. Compared with GTO, the new product has the characteristics of high speed turn on-off low loss and high switching frequency at high voltage. Because of the special characteristics of the SI-Thyristor, its control with the conventional driving circuit used for the GTO is insufficient. Then, a new and compact gate drive is developed. It is composed of a driving circuit capable of driving at high-voltage with high-speed and high-frequency and an isolated controlled power supply. The driving circuit is presented and proposed as an efficient tool for the SI-Thyristor control.

High power buck-boost type DC-DC converter applied to the auxiliary power source of the electric railway rolling stock

A high power buck-boost DC-DC power converter operating in the discontinuous reactor current mode, in which the size and weight of two-winding reactors are reduced to less than one-half of those of the same type of power converter operating in the continuous one, is presented. This converter is applied to an auxiliary power source in electric railway rolling stock. The proposed DC-DC power converter is analyzed and its usefulness is confirmed by experiments.<<ETX>>

Static inverter for railway electric coaches utilizing booster inverter

Connecting the current type inverter and voltage type inverter in series, the new type of inverter that controls the dc voltage or ac voltage of voltage type inverter by controlling the functioning phase between both phases is introduced in this paper. This inverter serves useful as de-dc converter or dc-ac inverter. This paper deals mainly with the function as dc-dc converter.

A novel test equipment for resonant circuits in high input voltage soft switching type DC-AC inverters and DC-DC converters

Recently, soft-switching techniques have been gradually introduced into DC-AC inverters and DC-DC power converters. The resonance phenomena generated by the inductor and capacitor are usually employed to achieve the soft-switching of main power switches and diodes in these power conversion circuits. In this paper, novel test equipment for resonant circuits is proposed and analysed, enabling the examination of the performance characteristics of the inductor and capacitor in high-voltage resonant circuits by using a relatively low voltage power supply.