Hideki Ayano

A Novel Technique for Reducing Leakage Current by Application of Zero-Sequence Voltage

This paper proposes a technique for reducing the leakage current flowing into a power source as a conducted noise. This leakage current may have an adverse effect on the peripheral equipment, e.g., causing malfunctions. The proposed technique requires us to add a zero-sequence voltage to the output voltage reference of the inverter. The zero-sequence voltage can be controlled without affecting the driving characteristics of the motor. In a motor drive range, a counter electromotive force increases with an increase in the motor speed. The proposed technique, therefore, controls the zero-sequence voltage as a function of the inverter output frequency; as a result, a stable motor drive and reduction in the common-mode current are realized simultaneously. Simulation and experimental results prove the validity of the proposed technique.

A Controller Tuning for 2-Mass System Using Closed-Loop Transient Data

Abstract This paper proposes a velocity controller tuning method for 2-mass system that is the first approximation of mechanical resonant systems. The method requires only one-shot transient input/output (I/O) data of the 2-mass system under closed-loop operation to tune the controller. The data is used to estimate the frequency response of the system and to model the system in frequency domain. The closed-loop system that consists of the model of the 2-mass system and the model-based controller designed by the model is introduced as the reference model for the Fictitious Reference Tuning (FRIT) to compensate the modeling error. The usefulness of the method is shown by numerical examples of the controller tuning for the velocity control system of a 2-mass system.

A novel technique for reducing leakage current by application of zero-sequence voltage

This paper proposes a technique for reducing the leakage current flowing into a power source as a conducted noise. This leakage current may have an adverse effect on the peripheral equipment, e.g., causing malfunctions. The proposed technique requires us to add a zero-sequence voltage to the output voltage reference of the inverter. The zero-sequence voltage can be controlled without affecting the driving characteristics of the motor. In a motor drive range, a counter electromotive force increases with an increase in the motor speed. The proposed technique, therefore, controls the zero-sequence voltage as a function of the inverter output frequency; as a result, a stable motor drive and reduction in the common-mode current are realized simultaneously. Simulation and experimental results prove the validity of the proposed technique.

Experimentally verification of the characteristic of a single-phase line-to-line 7-level inverter under loaded condition

This paper validates the characteristics of the single-phase line-to-line 7-level inverter under loaded condition (890W). The feature of this inverter is that the circuit is the same as a conventional A-NPC type 3-level inverter, but the DC voltage sources are asymmetry. The voltage value of one DC voltage source is set twice as large as that of the other. Simulation results show that the voltage THD of the proposed 7-level inverter can be less than those of the conventional 2-level inverter, the A-NPC 3-level inverter. Experimental results of the proposed 7-level inverter, where a dead time and its compensation are implemented, are mostly in agreement with the simulation results. Furthermore, when the output voltage reference is large, the proposed 7-level inverter can reduce the current THD and the amount of electric charges supplied from each cell battery in the voltage sources can be almost equalized.

Evaluation of primary-side power supply coil shape to expand the charging area in a contactless power transmission system

This paper deals with the magnetic flux distributions when the shape of the primary-side power supply coil is changed to expand the charging area in a magnetic resonance power transmission system. In the conventional system, one primary-side power supply coil generally supplied to one secondary-side power reception coil. However, if the one primary-side power supply coil can supply to several secondary-side coils, the problem of many power cables is solvable. In this case, it is required that the primary-side coil enlarges the power supply distance and power supply range. This paper addresses the characteristics of the power supply ranges when the solenoid coils are used as the primary-side coil. The coil lengths of the solenoid coils are changed to 20 mm, 100 mm and 200 mm, and the diameter of each coil is 61 mm. The power supply ranges are measured with the receiving antenna of 25 mm diameter. Though the coil length of the solenoid coil hardly influences the power supply range in the axial direction, the power supply range in the radial direction is extended.