Yugo Tadano

Direct Space Vector PWM Strategies for Three-Phase to Three-Phase Matrix Converter

This paper proposes 3 types of new direct space vector modulation methods for three-phase to three-phase matrix converters. The space vector modulation method allows a direct understanding of switching patterns and their characteristics from the viewpoint of analysis and control. Output voltage harmonics and switching losses can be reduced across the entire voltage region by making use of the direct AC/AC conversion approach. The switching count can be reduced even further by fully utilizing the output current detection value. The conventional virtual indirect conversion approach is first described and then the selection method of space vectors is explained along with the duty calculation technique in direct space vector modulation. Finally, the validity of the proposed method is proven from simulation and analysis results.

Independent control of input current and output voltage for Modular Matrix Converter

This paper presents independent control of input current and output voltage for Modular Matrix Converter (MMxC). The MMxC is a multi-level converter without a transformer that converts from the high voltage AC to high voltage AC with arbitrary amplitude and frequency. The control method is difficult due to the simultaneous control of the input current and output voltage. The authors propose a novel control method that is divided into two parts of the positive-sequence circuit for the input current control, and the zero-sequence circuit for the output voltage control. The effectiveness of the proposed control method has been verified by simulations and experiments.

Periodic learning suppression control of torque ripple utilizing system identification for permanent magnet synchronous motors

This paper introduces two torque ripple suppression control methods for permanent magnet synchronous motor. With a system identification technique, the system model from compensating current input to torque detection output can be expressed as the speed-adjustable 1-dimension complex vector in the coordinate system synchronizing with the torque ripple frequency. The first method introduces a periodic learning I-P control system of compensating current to create the feed-forward compensation tables. The second introduces a speed-adjustable periodic disturbance observer which can improve the transient suppression characteristics. Both methods are suitable for the adjustable-speed drive, so the control parameters and reference model can be adjusted automatically. The most important thing is with these methods excellent performance for mechanical resonance suppression caused by torque ripples can be gotten. And this paper shows the analysis and experimental results to support the methods.

Parameter estimation of PMSM driven by PWM inverter based on discrete dynamic model

Most PMSM parameter estimation techniques assume steady state to avoid model error caused by current derivative but have difficulty in collecting data rich enough to estimate four parameters of PMSM in regular operation. Parameter estimation based on dynamic model has advantages such as simultaneous estimation of four parameters, data collection from regular operation and faster estimation. In this research, PMSM parameter estimation based on the discrete dynamic model using data synchronously sampled at the top and bottom of triangular carrier of a PWM inverter is proposed. The influence of model errors on the estimation due to discretization method, dead time and resolution of PWM are investigated in a simulation study. Immunity of the proposed estimation to the dynamic change in current is tested in the experiment.

Compensation of the current measurement error with periodic disturbance observer for motor drive

Output current of general inverter is controlled based on the information of current sensors which are placed on the output. However, these sensor outputs have gain error and offset which are depending on the peripheral components and the accuracy characteristics of current sensor. Current control performance can be deteriorated a control method which uses a periodic disturbance observer to suppress vibration. We have developed a periodic disturbance observer as a control method for vibration suppression. Focusing on the current sensor error, it may cause the vibration of a specific frequency. Then, this paper proposes a current sensor error compensation control method by applying a periodic disturbance observer. To suppress the harmonic current online by this approach, the current control performance can be improved.

Vector controlled induction motor drives with electrical double layer capacitor

This paper proposes a direct current (DC) power supply circuit consisted of a battery and an electrical double layer capacitor (EDLC). Inverter-fed induction motor (IM) drive is controlled using the proposed power supply circuit. This power supply circuit can be composed of a power regeneration system consisting of the battery connected to the EDLC through a step-up and down chopper. By switching control of the step-up and down chopper, it can control charge and discharge of the EDLC. Therefore, the EDLC enables us to achieve the giving and receiving of DC with the inverter. When the inverter-fed IM drive generates a power with regenerative braking, the power is charged to the EDLC. The EDLC discharges the charged power when the inverter-fed IM drive is accelerated or load is added to the inverter-fed IM. By means of these works, the proposed power supply circuit can reduce the load of battery. The utility of the proposed method is examined through computer simulations.

Adaptive control method for an induction motor with improved characteristics during regenerating mode

In this paper, the use of an adaptive control method for an induction motor is described. Using the conventional adaptive control method, it is possible to stably estimate the inverse time constants (both primary and secondary) during the powering mode. However, it becomes unstable during the regenerating mode. To solve this problem, there is a method that changes the adaptive control gain in the regenerating mode to make the control stable. This paper proposes an adaptive control method that can stably estimate the inverse time constant without affecting the driving mode. The principle of the proposed method is explained and the simulation results are shown.