Yuma Fujii

Electromagnetic noises and efficiency evaluations of three-phase ZVS-PWM inverter with new resonant AC link snubbers

This paper presents a novel prototype of three-phase voltage source type zero voltage soft-switching (ZVS) inverter using the main and auxiliary IGBT power module packages in order to reduce their switching power losses as well as electro-magnetic conductive and radiative noises. A single inductor-based resonant AC link snubber circuit specified as one of auxiliary resonant commutation snubbers to achieve the ZVS for the three-phase voltage source type inverter operating under a principle of specific instantaneous space voltage vector sinewave modulation is originally demonstrated as compared with the other types of resonant AC link snubber circuit topologies. In addition to this, its operation principle and unique features are described in this paper. The practical basic operating performances of the new conceptual instantaneous space voltage vector modulated three-phase voltage source soft-switching inverter are evaluated and discussed on the basis of waveforms quality evaluations on the output line to line voltage, power loss analysis, power conversion efficiency and electromagnetic conductive and radiative noise from an experimental point of view, comparing with three-phase voltage source hard-switching inverter.

Zero-Voltage and Zero-Current Soft-Switching PWM Inverter with a Single ARDCL Cell

This paper presents a zero-voltage and zero-current soft-switching (ZVZCS) PWM three phase inverter with a single auxiliary resonant commutation cell. All of the main switches in the three-phase inverter side can be turned on and turned off under zero-voltage and zero-current condition. The operating principle of proposed commutation cell is described, and the procedure to determine the optimum circuit parameters from the resonant equations is discussed. The performances of proposed ZVZCS three-phase inverter are discussed from the experimental and simulation points of view

Active auxiliary resonant snubber-assisted soft-switching PWM inverter with optimum gate pulse pattern sequences and its PV-system application

This paper presents an advanced circuit topology and optimum gate pulse patterns for the voltage source bridge type soft-switching PWM inverter, which incorporates a novel active auxiliary bridge commutation leg, associated quasiresonant snubbers as the improved ARCP snubber. In this voltage source type PWM inverter, all the main power switches and the auxiliary power switches can achieve the zero voltage soft-switching (ZVS) or the zero current soft-switching (ZCS). And the periodic steady state circuit operation of this quasiresonant bridge leg link snubber including the auxiliary switch is required to achieve the soft-switching commutation. The complete soft-switching commutation is possible only by determining the gate timing of the main switches and the auxiliary switches, and the circuit parameter design. So the special resonant current and the current and voltage sensor control circuit to achieve soft-switching commutation are not necessary for this resonant snubber. In addition, the optimum gate pulse pattern to minimize the power losses of the resonant snubber treated here. The DC divided middle point composed of the electrolytic capacitor is unnecessary.

A pulse current regenerative auxiliary resonant bridge leg link snubber-assisted three-phase soft switching PWM inverter

In this paper, a novel circuit topology of active auxiliary edge resonant snubber suitable for high power soft switching PWM inverter applications, which has some salient features as compared with previously developed auxiliary resonant commutated pole (ARCP) snubber is proposed in order to minimize the switching power losses of IGBTs in addition to the switching surge related electromagnetic noises in three-phase power conversion circuits on the basis of the sinewave PWM inverter and sinewave PWM PFC rectifier as well as bi-directional PWM converter used as the battery energy storage system. This resonant snubber-assisted inverter suitable for high power conversion is described and discussed on the basis of soft switching transition and commutation operation of the high efficient pulse modulated inverter. The working principle and operating characteristics of this active auxiliary snubber circuit are described, together with the practical design procedure of this unique edge resonant snubber. This paper shows actual efficiency vs. output power characteristic of three-phase soft switching PWM double converter system designed for 10 kVA UPS composed of three phase soft switching PWM rectifier and inverter. The total actual efficiency of three phase soft switching PWM double converter is 88.6% as compared with that of hard switching double converter is 87.0% under a rated load.