M. Ishibashi

Feasible performance evaluations of active resonant snubber-assisted three phase soft switching inverter

This paper presents an active resonant snubber-assisted three phase voltage source type soft switching inverter with space voltage vector modulation scheme which can operate under the principle of zero voltage switching (ZVS) condition. The steady-state performances of this digitally-controlled soft switching inverter which is suitable for high-power applications is illustrated and evaluated as compared with a hard switching inverter on the basis of experimental results.

Series-compensated inductor type resonant inverter using pulse density modulation scheme for efficient ozonizer

This paper presents a high-frequency voltage source-fed load-resonant IGBT inverter with a series-compensated resonant inductor for ozonizer power supply, which is characterized by the power control strategy on the basis of pulse density modulation (PDM). The inverter system configuration illustrated through the circuit modeling of the silent discharge-based ozone generating tube and high-voltage transformer. The state-of-the art ozonizer using a high-frequency load resonant inverter is demonstrated and its operating principle of the voltage-fed load-resonant inverter are described for the ozone generating tube. It is noted that the pulse density modulated series resonant high-frequency inverter using IGBTs makes an ozonizer power control scheme simple as well as improves the ozone generating characteristic. Thus, it is effective in improving the ozone producer efficiency. Finally, it is proved that the series load-resonant inverter type ozonizer developed in this paper provides stable silent discharge characteristics over a wide output power range from 10% to 100%.

Three-phase current-fed soft switching PWM converter with switched capacitor type resonance DC link

In this paper, a newly-proposed three-phase current-fed zero current soft switching PWM converter using a new switched capacitor type resonant DC link (RDCL) circuit is described, which is basically operated by the new conceptual optimum PWM pattern for efficient high-power utilization. The working principle, design approach and operating performances of this converter suitable for large capacity applications in industry are discussed. The effectiveness of this soft-switching optimum PWM converter with sinewave current shaping and unity power factor correction schemes is proved on the basis of experimental results.

New conceptual three-phase current-fed soft switching pulse width modulation converter with switched capacitor type resonant dc link

This paper presents a novel prototype of three-phase current-fed PWM converter with a switched capacitor type resonant dc link snubber circuit, which can basically operate under a principle of zero current soft switching commutation. The optimum PWM pattern-based control scheme proposed by the authors is effectively applied for this active converter. In this paper, the steady-state operating principle of a new converter circuit treated here is described. The practical design procedure of this converter is discussed from a theoretical point of view. The feasible experiment to confirm zero current soft switching commutation of this converter is concretely implemented and evaluated herein.

Space current vector modulated current source active converter with resonant snubber and current overlapping soft-commutation schemes

This paper presents a three-phase current source PWM converter with a single resonant DC link snubber which can operate under zero current switching (ZCS) commutation. The operation principle of this soft-switching converter is based upon the current overlapping soft-commutation and the resonant snubber soft-commutation. A new space current vector modulated control strategy of this converter is effectively implemented by applying the space vector pattern to minimize the operating number of auxiliary active switches under the resonant snubber soft-commutation.

Three-phase current-fed quasi-resonant converter with input side commutation inductors

This paper presents a new three-phase current-fed soft-switching PWM power converter. This converter utilizes two types of switching commutation schemes to improve the PWM current utilization rate. It is described that this power converter has effective performance of low THD and high current utilization rate by computer simulation results.

Three-phase current-fed converter with resonant snubber and commutation inductors

This paper presents a three-phase current source PWM converter with a single resonant DC link snubber which can operate under zero current switching (ZCS) commutation. The operation principle of this soft-switching converter is based upon the current overlapping soft-commutation and the resonant snubber soft commutation. A new space current vector modulated control strategy of this converter is effectively implemented by applying the space vector pattern to minimize the operating number of auxiliary active switches under the resonant snubber soft commutation.

A novel soft-switched current-fed converter with resonant snubber and current overlapping soft-commutation scheme

This paper presents a three phase current-fed space vector modulation converter with a single auxiliary active capacitor type resonant DC link snubber and commutation inductor which can operate under zero current switching (ZCS) commutation. The operating principle of this converter is based upon the current overlapping soft-commutation with the resonant snubber soft-commutation. A new space current vector modulated control strategy of this converter is effectively implemented by applying the space vector pattern to minimize the operating number of auxiliary active switches under the resonant snubber soft-commutation.

A novel three-phase, current-fed ZCS-PWM converter incorporating a single resonant DC link soft commutation snubber

This paper presents a novel prototype three-phase current-fed PWM converter with a switched-capacitor-type resonant DC link commutation circuit operating with a new optimum PWM pattern strategy, designed with consideration for a low-pass filter. This converter can operate based on the principle of zero current soft-switching commutation. First, the steady-state operating principle of this converter with a new resonant DC link snubber circuit is described in relation to an equivalent operating circuit, together with the practical design procedure of the switched-capacitor-type resonant DC link circuit. Second, the three-phase current-fed PWM converter with the switched-capacitor-type resonant DC link circuit is discussed from a theoretical viewpoint based on a design example. An actively delayed time correction method to compensate distorted currents due to a relatively long resonant commutation time is newly implemented in the open-loop control scheme so as to obtain a new optimum PWM pattern. Finally, an experimental setup of this converter is demonstrated in a laboratory to confirm the zero current soft-switching commutation of this converter. Comparative evaluations between current-fed hard-switching PWM and soft-switching PWM converters are implemented from the viewpoint of PWM converter characteristics.