Masami Fujitsuna

A Precise Model-Based Design of Voltage Phase Controller for IPMSM

This paper presents a model-based design method of voltage phase controller for IPMSM. The voltage phase controller controls the torque with the output voltage phase only in high-speed region where the inverter output voltage amplitude is saturated. However, voltage phase control cannot achieve quick torque response because it is designed in defiance of transient characteristic. Due to the nonlinear characteristic between torque and voltage phase, a model-based design has not yet been carried out. In this paper, a model-based design is proposed by linearizing the relationship between torque and voltage phase. The analysis of the proposed model describes that the plant is a nonminimum phase system. Simulation results and experimental results show the effectiveness of the model-based design method which uses the proposed model. Furthermore, the stable analysis shows that the conventional design method has low bandwidth due to an unstable zero of the plant.

Optimal control of PMSMs using model predictive control

Permanent magnet synchronous motors (PMSM) have been receiving much attention. In conventional current control systems, the inverter is regarded as an ideal amplifier. In this paper, we propose a novel model predictive control (MPC) based current control system that improves performance in cases where the inverter cannot provide the appropriate input. The effectiveness of the proposed method is illustrated through simulations and experiments. From a practical point of view, the computation delay must be considered. Thus, a modified control method is also proposed in order to improve performance of the system, the effectiveness of which is also shown through simulations and experiments.

Dead-time compensation in model predictive instantaneous-current control

Model predictive instantaneous-current control (MPIC), which was proposed in our earlier works, enables us to achieve better instantaneous current control using mathematical models of an inverter and permanent magnet synchronous motors (PMSM). However, the dead-time to avoid the short breakdown in the inverter is the main reason in the modeling error. If the modeling error is not ignorable, it is not possible to predict the current evolution using the model. Thus, in this paper, we analyze the influence of the dead-time in MPIC and propose a compensation technique for the dead-time so that the error of the predicted current is reduced. The effectiveness of the proposed method is verified through simulation and experiments.

Instantaneous-current control of PMSM using MPC: Frequency analysis based on sinusoidal correlation

We have proposed a novel approach for permanent magnet synchronous motors based on model predictive control. This paper describes a frequency analysis based on a single sinusoidal correlation in order to clarify the control performance of the model predictive instantaneous current control (MPIC). For MPIC, the proposed analysis method allows us to analyze the gain and phase characteristics which has not been discussed explicitly so far in other works.

Control method for IPMSM based on perfect tracking control and PWM hold model in overmodulation range

Interior permanent magnet synchronous motors (IPMSMs) are employed for drive motors of electric and hybrid vehicles. Therefore, the control method in overmodulation range of inverter is important for fast torque response and expanding operation range of IPMSM. In this paper, the control methods based on perfect tracking control and PWM hold model are proposed in overmodulation range. The proposed methods do not need to switch controllers in overmodulation range. One of the proposed methods simultaneously prevents windup phemonemon and voltage saturation which is caused by harmonic current with PWM hold model. Finally, simulations and experiments are performed to show the advantages of the proposed methods.

Torque ripple suppression control for PM motor with high bandwidth torque meter

PM motor drive systems are widely used in many industrial applications. However, PM motors have the fluctuation of the magnetic field distribution which produces the torque ripple. Dead time of the inverter, offset of sensors and current measurement errors lead to the torque ripple, too. In this paper, we proposed a torque ripple suppression method with PWM-hold model, in which the torque ripple is measured by a high-bandwidth torque meter. To suppress the torque ripple, we propose a method to generate the compensation signal by using the information from the torque meter. Finally, we show the advantages of the proposed method by simulations and experiments with a SPMSM.

Torque ripple suppression control for PM motor with current control based on PTC

PM motor drive systems are widely used for industrial drives. However, PM motors basically produce the torque ripple due to the fluctuation of the magnetic field distribution. Dead time of the inverter, offset of sensors and current measurement errors lead to the torque ripple, too. The torque ripple leads vibration noises. In this paper, we proposed a torque ripple suppression method based on perfect tracking control, in which the torque ripple is measured by a low-bandwidth sensor. Finally, we show the advantages of the proposed method by simulations and experiments with a SPMSM.

Speed Estimation Method utilizing Rotor Slot Harmonics Detected from Line Current for Speed Sensorless Drive of Ultra High Speed Induction Machine

Recently, development of power electronics technology has made it possible to realize ultra high speed machine and it has been expected in various applications. This research aims at sensorless control drive of induction machine in the ultra high speed region by utilizing rotor slot harmonics caused by structure of induction machine. In this paper, we proposed a novel speed estimation method utilizing rotor slot harmonics detected form line current for speed sensorless drive of ultra high speed induction machine. It is possible to detect the rotor slot harmonics with high signal-noise ratio by utilizing a harmonics model of IM and fast Fourier transform (FFT) with limitation of a detection band. Moreover, the effectiveness of the proposed method is confirmed by experimental result.

Position Sensorless control of PMSM with a low-frequency signal injection

In this paper, a new position sensorless control of PMSM for low speed and standstill by using a low-frequency signal injection is proposed. Conventional sensorless control method for a low speed range uses injection signal of a frequency around kHz. The problem with this approach is harsh acoustic noise by the injection signal. Low-frequency signal injection solve the problem of noise but it makes new problems as follows. One is that the filter for signal separation degrades the current control characteristics. The other, PLL(Phase Locked Loop) design for position estimation would be limited. To overcome these problems, we proposed a new position sensorless control methods for a low-frequency signal injection. The proposed method performs subtraction by using the specific frequency component estimated from known information such as motor model and injected signal. It achieves stable control by using a low frequency overlapping with the current control band.

Feedforward control for SPMSM with final-state control based on voltage limit circle with transient term

SPMSMs (Surface Permanent Magnet Synchronous Motors) are employed for many industrial applications. SPMSM drive systems should achieve quick torque response and wide operating range. For quick current response, authors proposed final-state control considering voltage limit. Final-state control drives an initial state to a final state with feedforward input during finite time. The proposed method achieved quick current control in field-weakening region but inverse response of q-axis current was caused. In this paper, a new feedforward control method which improves current response is proposed. Simulations and experiments are performed to compare two types of feedforward control method. In addition, current response under voltage limit is analyzed by the voltage limit circle of SPMSM with transient term.