Hiroki Ohtani

High Performance Motor Drive Technologies for Hybrid Vehicles

In this paper, latest motor drive technologies used for hybrid vehicles (HV), which are high output motor control and variable voltage system, will be introduced. Authors have researched and developed motor drive technologies through development of hybrid vehicles, which has been put into practical use to production vehicle. The developed motor drive system has the features of high efficiency, high power/weight ratio, and low-cost.

A novel multi-functional converter system equipped with input voltage regulation and current ripple suppression

This paper introduces a multi-functional converter system (MFCS) for HEVs, equipped with input voltage regulation and current ripple suppression. The MFCS consists of a motor, an inverter and a battery, and the battery connected to the neutral point of the motor. However, the basic type MFCS circuit have the advantage of omitting the DC/DC converter, it still needs an external inductor, or large current ripple arises, it causes loss, acoustic noise and vibration, and also has limitations in input voltage regulation range. To improve the MFCS, the two-motor type MFCS is proposed, the battery connected between the neutral points of two three-phase motors. When the two inverters are cooperated, the current ripple suppressed into 1/4.5 of the basic type. And it realizes wider input voltage regulation range than that of the basic type.

Development and testing of the torque control for the permanent-magnet synchronous motor

The purpose of this study is to develop a control method that increases the torque and the efficiency at all rotor speeds more than the ordinary current error feedback method. The method is composed of two compensators is proposed to achieve this purpose. One of the compensator controls the torque using the phase of voltages. Another one is the ordinary current error feedback. The validity of the proposed method is confirmed in the simulation and experiment examinations.