Koki Ogura

Comparative performance evaluations of IGBTs and MCT in single-ended quasi-resonant zero voltage soft switching inverter

The simple and low-cost operation at zero voltage soft commutation voltage-fed quasi-resonant PFM inverter is widely used, which is more suitable and cost effective for consumer induction heated cooking appliances. This paper presents feasible performance evaluations of each generation IGBT developed and MOS controlled thyristor (MCT) incorporated into the simplest voltage source type quasi-resonant PFM inverter operating in zero voltage soft switching transition mode for induction heated loads. New generation IGBT in addition to MCT have been improved in order to reduce their conduction power losses which are based on their lowered saturation voltage characteristics in addition to high current density. In the first place, each generation IGBT is respectively built and tested on the basis of a single-ended quasi-resonant PFM inverter circuit operating at zero voltage soft switching commutation. In the second place, the power loss-temperature analysis of the latest IGBT with a trench-gate structure is discussed and evaluated from an experimental point of view. In the third place, the further reduced saturation voltage and conduction power loss characteristics of attractive MCT are presented in comparison with the 3rd generation IGBT by using zero voltage high current density soft-switching inverter for consumer high frequency power application.

Next-generation battery-driven light rail vehicles and trains

Abstract Light rail vehicles (LRVs) have historically sourced power from overhead power lines. However, in recent years, catenary-free operations are fast gaining prominence. Catenary-free refers to the removal of the overhead power line equipments from the vehicle system. Power for such systems is sourced on-board energy storage devices. This chapter gives an overview of the next-generation battery-driven low-floor LRV named SWIMO, which includes an impressive technology, concept, and test results. The development concept for SWIMO has been to make a vehicle that is ‘good for people and the environment’ with the consideration of the aging of society and environmental concerns. In addition, catenary-free systems are gaining prominence, and more companies are entering the market. The examples of battery-driven train and LRV with commercial operations in Japan and France are presented from an innovative point of view.

Feedforward of grid line-to-line voltages for grid-connected inverter under the weak grid condition

Feedforward control is reliable for rejecting fast and dynamic voltage disturbances in the grid. Mainly this scheme is implemented based on phase voltages of the wye connected configuration. Under unbalanced and distorted grid-condition, the online conversion of line-to-line values into the phase values is unworkable. In order to exploit full advantages of feedforward controller, an appropriate modulator is needed. In this paper the feedforward of grid line-to-line voltages is used in lieu of phase voltages. The introduced feedforward method is implemented with implicit zero-sequence discontinuous pulse width modulation (IZDPWM) technique that is compatible for grid-connected inverters. Regardless the grid topology, IZDPWM exactly copies the distorting harmonics of the grid voltage. Hence, a sinusoidal current is injected to the grid. Moreover, for measuring the grid line-to-line voltages two sensors are required; hence overall system cost is reduced and control system reliability is increased.

Battery technologies for electric vehicles

This chapter gives a brief overview of the following types of vehicles: battery electric vehicle (BEV), plug-in hybrid electric vehicle (PHEV), and hybrid electric vehicle (HEV). It then provides a comprehensive summary of the electrochemical energy storage including Ni-MH battery, Li-ion battery, and advanced rechargeable battery. Battery chemistry is explained in a detailed manner including an abbreviated modelling approach. Also, the issues of battery-charging method, management, and monitoring are addressed. The chapter concludes with a discussion on battery cell voltage balancing and temperature monitoring in addition to the battery state-of-charge (SOC) estimation.

New conceptual high efficiency sinewave PV power conditioner with partially-tracked dual mode step-up DC-DC converter

This paper presents a novel circuit topology of a high efficiency single-phase sinewave PV power conditioner. This power conditioner is composed of time-sharing sinewave absolute pulse width modulated boost chopper with a bypass diode in the first power processing stage and time-sharing sinewave pulse width modulated full-bridge inverter in the second power processing stage operated by time-sharing dual mode pulse pattern control scheme. Its unique operating principle of two power processing stage with time-sharing dual mode sinewave modulation scheme is described with a design example. This paper also proposes a sinewave tracking voltage controlled soft switching PWM boost chopper with a passive auxiliary edge-resonant snubber. The new conceptual operating principle of this novel single-phase sinewave power conditioner related to solar photovoltaic generation system is presented and discussed through the experimental results.

Smooth filtering DC link type soft-switching two-stage power conditioner

This paper introduces a power conditioner with two stages of power conversions. The first stage is the DC boost chopper with the passive auxiliary resonant snubber-assisted soft-switching circuit. The second stage is the sinewave PWM inverter with the active auxiliary resonant snubber-assisted soft-switching circuit. The inverter part is made of half-bridged configuration to limit the number of the circuit elements and to be connected to a normal resistant load. Finally, it is shown that all power switches are operated on the basis of soft-switching and the results are verified by both computer simulations and experiments.

A novel PV power conditioner operating under time-sharing sinewave tracking boost chopper-fed inverter and its extended bidirectional topology

This paper presents a new conceptual circuit topology of a high efficiency single-phase sinewave PV power conditioner with a compact intermediate film capacitor DC link stage. It consists of time-sharing partial sinewave absolute pulse width modulated boost chopper with auxiliary bypass diode in the first power processing stage and time-sharing partial sinewave pulse width modulated polarity changing full-bridge inverter in the second power processing stage operated by timesharing dual mode pulse pattern control scheme. Its unique operating principle of two power processing stages with timesharing dual mode sinewave modulation scheme is described with a design example. The operating principle of the novel single-phase sinewave power conditioner for the solar photovoltaic generation system is presented and discussed through the experimental results together with its control processing. Furthermore, the extended bidirectional power conditioner delivered from this proposed unidirectional power conditioner is described for battery / electric double layer capacitor (EDLC) charging and discharging applications.