Hidenori Hara

The matrix converter drive performance under abnormal input voltage conditions

The matrix converter (MC) is a direct frequency conversion device with high input power quality and regeneration capability. As a device without energy storage elements, it has higher power density than pulse-width modulation (PWM) inverter drives. However, for the same reason, the AC line side disturbances can degrade its performance and reliability. In this paper, the behavior of the MC drive under abnormal input line voltage conditions has been investigated. A technique to eliminate the input current distortion due to the input voltage unbalance has been developed and its feasibility proven via computer simulations and laboratory experiments. The power line failure behavior has also been investigated and the rapid restarting capability of the MC drive has been demonstrated via laboratory experiments.

Development of MCs and its Applications in Industry [Industry Forum]

An MC is a direct AC-AC converter that has benefits of high reliability, small size, and high efficiency over a conventional PWM converter-inverter system. This article introduced the Yaskawa MC product specifications, applications, and techniques that helped commercialization of a low-voltage and medium-voltage MC. The 9-114 kVA (200 V and 400 V classes) for a low voltage MC and 200-6,000 kVA (3.3 kV, 6.6 kV) for a medium-voltage MC have thus far been commercialized. Three typical applications of an MC were also introduced along with the related technology that helped to achieve desired results for each application. The application of an MC is still expanding to other fields in industry. Authors are continuing their efforts in improving performance and expanding the product lineup.

Integrated Filters and Their Combined Effects in Matrix Converter

Matrix converter has a topology that inherently exhibits sinusoidal input current waveforms and has small output voltage steps. This paper proposes to integrate the matrix converter with filters, which provide lower EMI, lower common-mode current, lower shaft voltage, and sinusoidal output voltage waveforms. A salient aspect of the proposed integration is its ability to significantly reduce the value of the input EMI filter capacitors and still meet strict EMT regulations. This helps in reducing the ground leakage current, which in the past has been a serious limitation in applying EMI filters with low ground currents for human and cattle safety.

Analysis and evaluation of bi-directional power switch losses for matrix converter drive

The matrix converter (MC) is a bidirectional AC/AC conversion device that generates variable-voltage variable-frequency output from ac voltage utility. Since power topology and switching rules of MC are quite different from voltage source inverter (VSI), power device loss analysis based on VSI topology cannot be applied to MC. In this paper, analysis method for evaluation of bidirectional switch losses of MC is proposed. Variation of collector-emitter voltage and current distribution in bidirectional IGBTs are investigated at various operating conditions for power loss analysis. The validity of the proposed analysis has been verified through the simulations and the experimental results with 7.5 kW MC driven-AC drives system.

Common-mode voltage characteristics of matrix converter-driven AC machines

This paper investigates the common-mode voltage characteristics induced by PWM switching of the Matrix Converter (M/spl times/C). Since the three-phase matrix converter has 27 output voltage vectors available, different common-mode voltage patterns exist even with the same line-to-line output voltages. High common-mode dv/dt contributes high leakage currents to the ground through the parasitic capacitances. Since output voltage vectors can be grouped according to the magnitude of common-mode voltage, PWM patterns should be designed to select the low common-mode voltage vector groups satisfying the requirement of output voltages and input currents. In this paper, practical PWM patterns of M/spl times/C are illustrated and their common-mode voltage characteristics are presented. A new PWM method is proposed and discussed considering both low common-mode voltage and low dv/dt in the PWM pattern. The results are also compared with the data obtained by the Voltage Source Inverter (VSI).

Output voltage distortion in matrix converter by commutation of bi-directional switches

The matrix converter is an AC-to-AC conversion device without intermediate DC link and the associated large capacitive filter. Three-phase matrix converter consists of nine bi-directional switches, which allows PWM control of input and output currents. Commutation from one switch to another is important for reliable operation. During commutation sequence, unwanted output voltage distortion occurs because actual commutation is dependent on magnitude of input voltage and direction of output current. In this paper, output voltage distortion during current commutation between bi-directional switches is analyzed and effective compensation method is proposed. The feasibility of the analysis results is proved by experimental results.

A wide speed range high efficiency EV drive system using winding changeover technique and SiC devices

The Silicon Carbide (SiC) based devices will become the mainstream in the motor drive technology in the near future. These next generation power devices give benefits of lower losses, higher voltage, and high temperature operation in the power conversion system, realizing its downsizing and high power density. The winding change over technique, on the other hand, is useful to extend the speed control range with high efficiency of ac motors. This paper describes the effects of using high power SiC MOSFET and SiC SBD, together with the electronic winding changeover technique in the EV motor drives.

Integrated filters and their combined effects in matrix converter

A matrix converter has a topology that inherently exhibits sinusoidal input current waveforms and has small output voltage steps. This paper proposes to integrate the matrix converter with filters, which provide lower electromagnetic interference (EMI), lower common-mode current, lower shaft voltage, and sinusoidal output voltage waveforms. A salient aspect of the proposed integration is its ability to significantly reduce the value of the input EMI filter capacitors and still meet strict EMI regulations. This helps in reducing the ground leakage current, which in the past has been a serious limitation in applying EMI filters with low ground currents for human and cattle safety

Bidirectional dc-ac conversion topology using matrix converter technique

The matrix converter is a power conversion topology, directly connecting the input and output with bidirectional switches. It has advantages such as high reliability and long life, bidirectional power flow and reduced current harmonics. This paper proposes a bidirectional dc-ac conversion topology with step-up and step-down capabilities using matrix converter technique. Detail of circuit operation and experimental results for various operating conditions will be described using a 1.0kW prototype.

Application of modular matrix converter to wind turbine generator

This paper introduces a new method of generator brake torque control during Fault Ride Through (FRT) drive for a multi level matrix converter of wind power system. It may be exist that a generator speed become over speed during FRT drive. In this case, a generator has to be fixed brake torque. In the past, generator brake torque control during FRT drive for a matrix converter is impossible. However, in this paper, concept of brake torque control method and compatible method of the torque control and FRT control are introduced. Then, fundamental simulation indicates effecting of the propose method. It is expected that safety FRT drive is realization by the proposed method.