Tetsuya Etoh

DC rails side diode clamped-active edge resonant PWM DC-DC converters with HF link

This paper presents a new circuit topology of active edge resonant snubbers-assisted soft switching symmetrical PWM inverter type DC-DC high power converter with a high frequency planar transformer. Its operating principle is described by using switching mode equivalent circuits, together with its unique features. The performance evaluations of its experimental setup are actually illustrated on the basis of the power loss analysis. The practical effectiveness of new DC-DC converter treated here is proved for low voltage and large current DC output implementation. The extended circuit topologies of DC-DC converter treated here are also demonstrated and discussed in this paper.

32 V-300 A/60 kHz edge resonant soft-switching PWM DC/DC converter with DC rail series switch-parallel capacitor snubber assisted by high-frequency transformer parasitic components

The conduction losses of the active switches can be lowered, which are connected to the primary side of extremely step-down high frequency transformer because of low voltage large current rectifier configuration. This paper presents two new circuit topologies of DC busline side active edge resonant snubber assisted soft-switching PWM full-bridge DC-DC converter acceptable for either utility AC 200 V-rms or AC 400 V-rms input voltage source. One topology of proposed DC-DC converters is composed of a typical voltage source-fed full-bridge high frequency PWM inverter using DC busline side series power semiconductor switching devices with the aid of a parallel capacitive lossless snubber. All the active power switches in the full-bridge arms and DC busline can achieve ZCS turn-on and ZVS turn-off commutations and the total turn-off switching power losses of all active switches can be reduced for high-frequency switching action. It is proved that the more the switching frequency of full-bridge soft switching inverter increases, the more soft-switching PWM DC-DC converter with a high frequency transformer link has remarkable advantages for its efficiency and power density as compared with the conventional hard-switching PWM inverter type DC-DC converter. In this paper, another modified version topology of utility AC 200 V-rms grid-connected soft switching DC-DC converter mentioned above is also implemented and evaluated, which is more suitable for utility 400 V-rms grid power source. The effectiveness of these new DC-DC converters topologies is proved for low voltage and large current high efficiency DC-DC power supplies as TIG are welding machine from a practical point of view.

Novel input DC buslines side active soft- switching cells-assisted symmetrical PWM DC-DC converters with center-rapped HF transformer link rectifier

This paper deals with a new circuit prototype of two active edge resonant cells-assisted soft-switching symmetrical PWM half-bridge inverter type DC-DC high power converter employing a high frequency planar transformer with center-tapped secondary windings and rectifier with choke-input. Its operating principle is described in detail by using switching mode transition equivalent circuits which is determined under particular switching pulse timing pattern scheme as symmetrical PWM strategy, together with its unique inherent features. The performance evaluations of its experimental PCB converter setup using IGBT power modules are actually illustrated on the basis of the power loss analysis vs. switching frequency. The practical effectiveness of new high frequency isolated DC-DC power converter treated here is particularly proved for low voltage and large current DC output implementation as high performance arc welding machines in industry. Moreover, the extended circuit topologies of DC-DC high power converter treated here and selective dual mode symmetrical PWM scheme operating at soft commutation are also demonstrated for not only large current and low voltage setting but also low current low voltage conditions.

A New Soft-Switching PWM High Frequency Half-Bridge Inverter Linked DC-DC Converter with Diode-Clamped Active Edge Resonant Snubbers

In this paper, the novel circuit topology of half-bridge soft switching PWM DC-DC power converter with a high frequency planar transformer link was presented. The operating principle and switching pattern of the half-bridge soft switching PWM DC-DC power converter described for 40 kHz, 36 V and 400 A output were illustrated and discussed for low voltage and large current output applications such as telecommunication and automotive applications. The power loss analysis of the proposed soft switching DC-DC power converter was discussed and evaluated as compared with hard switching PWM DC-DC power converter with a high frequency link. The practical effectiveness of the proposed DC-DC power converter operation under soft switching PWM scheme was actually proved from a practical point of view and the high efficiency and power density of this converter could be achieved on the basis of experimental results for low voltage and large current power supplies.

New auxiliary active lossless snubber-assisted full bridge soft switching PWM high frequency inverter-fed DC-DC power converter

This paper deals with a novel full bridge circuit topology of high frequency transformer isolated soft switching PWM inverter type DC/DC power converter. The zero voltage soft switching PWM DC/DC power converter employing an input DC rail series switch and parallel capacitor assisted by high frequency transformer parasitic component is proposed and developed for high performance TIG and MIG arc welding in industry. Its operating principle in stead state is described by introducing switching mode equivalent circuits. The operating performances of 32 V-300 A/60 kHz soft switching PWM inverter fed DC-DC power converter using IGBT module package are illustrated on the basis of experimental results along with its power loss analysis