Kouki Matsuse

DSP-based speed adaptive flux observer of induction motor

A method of estimating the speed of an induction motor is presented. This method is based on the adaptive control theory. Experimental results of a direct field oriented induction motor control without speed sensors are presented.<<ETX>>

Speed sensorless field oriented control of induction motor with rotor resistance adaptation

The authors present a method for estimating simultaneously the motor speed and the rotor resistance of an induction motor by superimposing AC components on the field current command. In addition, a rotor resistance adaptive scheme is proposed in order to decouple the rotor resistance adaptation with the motor speed variation. The validity of the proposed method has been verified by simulation.<<ETX>>

High-response flux control of direct-field-oriented induction motor with high efficiency taking core loss into account

Stator core loss has significant adverse effects when an induction motor is controlled by the conventional field-oriented method. Therefore, taking core loss into account should make it possible to control the torque very precisely. In this paper, a direct-field-oriented induction motor with a deadbeat rotor flux controller was developed. The method ensures maximum efficiency in the steady state without degradation of the dynamic response. Simulation and experimental results have demonstrated that this method has higher efficiency and good speed response without any degradation in the transient characteristics.

New adaptive flux observer of induction motor for wide speed range motor drives

A flux observer of an induction motor with a parameter adaptive scheme is proposed. The parameters identified adaptively are stator and rotor resistance, which vary with motor temperature. The stability of the proposed adaptive flux observer is proved using Lyapunovs theorem. The robustness of the induction motor drive system with the proposed flux observer is shown. The adaptive scheme can also be applied to estimate motor speed without speed sensors.<<ETX>>

Voltage-balancing method for IGBTs connected in series

This paper presents a new method for balancing voltages of series-connected insulated gate bipolar transistors (IGBTs). This method can be implemented only by adding simple circuits to the gate drive system of the IGBTs, and its effect of balancing the IGBTs collector-emitter voltages during the switching transients is remarkable. This principal strategy and experimental results with series-connected IGBTs are first described. After that, further experimental results are shown from the switching tests of four 2.5-kV flat-packaged IGBTs connected in series. Through the switching tests, superior characteristics of the proposed method have been confirmed.

Fundamental characteristics of five-level double converters with adjustable dc voltages for induction motor drives

In this paper, two kinds of control strategies for a three-phase five-level double converter are described on the assumption that the converter is applied to an induction motor drive system. The purposes of the proposed control strategies are to correct voltage imbalance of the DC-bus capacitors, to keep the input power factor at near unity, and to achieve an adjustable-speed drive. Characteristics of the converter operated by each of the two control strategies are examined and the validity is verified by experiments using a 3.7-kW induction motor.

An Overmodulation Method for PWM-Inverter-Fed IPMSM Drive With Single Current Sensor

In order to lower the cost and expand the working range of pulsewidth modulation (PWM)-inverter-fed interior permanent magnet synchronous motor drives, the control methods under the overmodulation mode with only a dc-link current sensor are investigated. The space vector modulation of the PWM inverter is analyzed in detail, and an adjustment scheme for the reference voltage vectors is developed to fulfill the requirements by phase current reconstruction under overmodulation. Furthermore, in order to simplify the control process and reduce the control errors, a specified overmodulation method based on the superposition principle is proposed for the PWM inverter with phase current reconstruction, which overcomes the shortcoming of the PWM adjustment scheme. Experimental results demonstrate the feasibility and the effectiveness of the proposed control method, which realizes the single current sensor overmodulation control with maximum voltage transfer ratio.

Voltage balancing method for IGBTs connected in series

This paper presents a new method to balance the voltages of the series connected IGBTs. This method can be realized only by adding simple circuits to the gate drive system of the IGBTs, and its effect of balancing the IGBTs collector-Emitter voltages during the switching transients is remarkable. Principal of this strategy and experimental results with series connected two IGBTs are described firstly. After that, further experimental results are set forth, which are switching tests with four 2.5 kV flat-packaged IGBTs connected in series. Through the switching tests, superior characteristics of the proposed method have been confirmed.

Speed sensorless field oriented control of induction machines using flux observer

Speed sensors are required for the field oriented control of induction machines. These sensors reduces the sturdiness of the system and make it expensive. Therefore, a drive system without speed sensors is required, This paper reviews speed sensorless induction motor drive methods using flux observers including Kalman filters.<<ETX>>

Characteristic Comparison between Five-Leg Inverter and Nine-Switch Inverter

This paper presents a characteristic comparison between a five-leg inverter and a nine-switch inverter. The five-leg inverter and the nine-switch inverter is a single inverter that can drive two AC motors independently. Concretely, we show a circuit architecture of both inverters, a modulation method for an independent drives and a division of voltage utility factor. Moreover, investigate about the inverter losses and a switching device capacity in driving two AC motors independently and adapting a control method to decrease the inverter losses.