Shuji Tomura

A new isolated multi-port converter using interleaving and magnetic coupling inductor technologies

This paper proposes a new multi-port converter with interleaved magnetic coupling technologies. With the focus on the impedance behavior of coupled magnetic components and the control parameters, this multi-port converter integrates one isolated dc-dc converter and two multi-phase boost converters, and controls these topologies independently. The proposed converter has the capability to connect four dc applications or sources in total, and so brings significant cost reduction and improves the total loss consumption of power systems. In addition, magnetic isolation brings high reliability of complex power systems such as electric vehicles or grid-connected industries. In this paper, the basic circuit behavior is verified by theoretical considerations and experiments. An example of the proposed circuit as a multifunctional dc power system is demonstrated with the simulation results. Such an approach could bring about variable application fields to dc electric power systems.

Analysis and Design of a Multiport Converter Using a Magnetic Coupling Inductor Technique

A novel multiport dc-dc converter with a coupling magnetic inductor is analyzed and designed. The proposed circuit integrates two multiphase converters and one isolated dc-dc converter. These converters can be controlled independently in one circuit by adjusting the duty ratio and phase angle difference. There are four dc ports in the circuit, and the dc power can be delivered multidirectionally among the four dc ports. In this paper, a 1.5-kW prototype of the multiport converter was constructed and successfully operated under full power. The experimental results confirm the theoretical analysis, and the conversion efficiency is above 90% over a wide range of output power. In addition, an example of a multifunctional power conversion system using the multiport converter is demonstrated.

Development of Vibration Reduction Motor Control for Hybrid Vehicles

The purpose of the study is to develop a vibration- reducing control method for the motor-generators in hybrid vehicles. To achieve this, two types of controller were developed. The first reduces vibration due to engine torque ripple at engine start. The second reduces drivetrain vibration. The effectiveness of these controllers in reducing vibration was confirmed experimentally.

Analysis and design of a multi-port converter using a magnetic coupling inductor technique

In the present paper, a novel multi-port converter with coupled magnetic components is analyzed and designed. The proposed circuit integrates two multi-phase converters and one isolated dc-dc converter. These converters can be controlled independently and simultaneously by duty cycle and phase-shift modulation, because the impedance behavior of magnetic components is different for each converter. A 1.5-kW prototype of the multi-port converter has been constructed and successfully operated under full power at a switching frequency of 40 kHz. The experimental waveforms confirm the theoretical analysis, and the conversion efficiency is above 90% over a wide range of output power. In addition, loss analysis is carried out in order to define the critical parts of the proposed converter.

1.8MHz isolated DC-DC converter with multitransformer structure for automotive applications

This paper discusses a MHz isolated HV/LV DC-DC converter for automotive applications. The proposed circuit is constructed with a low cost structure by using multitransformer and Si-MOSFETs to achieve frequency multiplying. Three circuit configurations namely, cascaded-type, parallel-type and cascaded-parallel-type, are considered and discussed. Fundamental control and switching behaviors are explained. A prototype based on cascaded-parallel-type was constructed to verify the validity of control theory. The experimental results show that 84% efficiency is achieved at 1.8MHz, and FFT analysis of the common mode current was evaluated to show the effectiveness of the proposed technique.