Hideaki Iura

Three years of industrial experience with sensorless ipmsm drive based on high frequency injection method

This paper introduces three years of industrial experience with sensorless interior permanent magnet synchronous motor (IPMSM) drive based on high frequency injection method (HFIM). In 2008 the first commercial general purpose inverter with sensorless control based on HFIM was launched. The HFIM enabled the sensorless IPMSM drive to control torque and speed under ultra-low speed region including zero stator frequency, which brought the expansion of the application field. The feature also realized the position control. Owing to the control performance and the sensorless feature on the reliability and the space-saving, the sensorless drive has been employed to direct drive applications with great expectations. As successful applications, a lift, a compressor, and an injection molding machine are introduced in this paper.

An Estimation Method of Rotational Direction and Speed for Free-Running AC Machines Without Speed and Voltage Sensor

This paper presents an estimation method of rotational direction and speed for free running AC machines driven by an inverter without speed and voltage sensor. The method has four estimation modes, and the method utilized only the measured phase current of machines. The amplitude of current during the estimation is suppressed to lower levels such as the exciting current, which is smaller than the rated value. Good performance of this method is confirmed by the experiment.

Hybrid sensorless control of IPMSM Combining high frequency injection method and back EMF method

This paper introduces a new hybrid sensorless control of interior permanent magnet synchronous machines (IPMSM) combining high frequency injection and back EMF based method. The proposed control system realizes position, speed, and torque control in the entire speed range. Owing to the reliability and the space-saving feature, the sensorless control is applied to direct drive applications with great expectations. As successful applications, an injection molding machine and a compressor are introduced in this paper. Experimental results show the effectiveness to the required specification of the control modes.

Hybrid sensorless control of IPMSM for direct drive applications

This paper presents a new hybrid sensorless control of interior permanent magnet synchronous machines (IPMSM) for direct drive applications. The control combines both high frequency injection and back EMF based method, and realizes position, speed, and torque control in the entire speed range. Owing to the reliability and the space-saving feature, the sensorless control is applied to direct drive applications with great expectations. As successful applications, an injection molding machine and a compressor are introduced in this paper. In each application, the optimally designed IPMSM for the sensorless control is employed. The design concepts of the application specific machine considering the control performance are also introduced. Experimental results show the effectiveness to the required specification of the control modes.

Position sensorless control for synchronous reluctance machine based on instantaneous power optimization

This paper proposes a new method of position sensorless control for synchronous reluctance machine (SynRM). The position sensorless scheme is based on the instantaneous power optimization the feature of which takes a specific control axes on reactive and real power and realizes both rotor speed estimation and tracking to the point of the maximum torque per current. Adopting the signal injection onto the phase angle of the current, the point of the maximum torque operating per current can be traced without dependency on the machine parameters. The effectiveness of the method is verified by experimental results.

An estimation method of rotational direction and speed for free running AC machines without speed and voltage sensor

This paper presents an estimation method of rotational direction and speed for free-running ac machines driven by an inverter without speed and voltage sensor. The method has four estimation modes, and it utilizes only the measured phase current of machines. The performance of the proposed method is verified through the experiments for both permanent-magnet synchronous motor and asynchronous machines.

Robust active damping technique for three-phase PWM converter connected to power grid with unknown inductance

The PWM converter includes a low-pass filter in order to remove the high-frequency current that flows to the power grid. The low-pass filter is composed of two reactors and a capacitor (LCL-filter). The LCL-filter is the gain characteristic that attenuates by the high frequency band, and can eliminate the career ripple of the current. However, LCL-filter has a strong resonance characteristic. When the power grid current resonates with a high frequency, the equipments connected to the same power grid are harmfully affected. In order to control this resonance, passive damping and active damping are used. However, both methods suffer from several problems. A passive damping is a method of controlling the resonance by the damping resistance. The generation of heat by the loss of resistance becomes a problem often. The active damping is a control technology that controls the resonance without using the damping resistance. The active damping has both of the sensor method and the sensor-less method. The active damping methods with sensor require the use of an additional sensor. When active damping is used without a sensor, it becomes more sensitive to the power grids inductance changes. Especially, in the case of an extreme increase in the power grids inductance, problems with LCL resonance and ACR deterioration occur. When the ACR response is deteriorated, the power grid is affected by low frequency oscillation, making the power supply unstable. All equipment connected to this power grid is harmfully affected. There are few examples of low frequency oscillation in conventional active damping technologies. It is possible to control the resonance of the LCL-filter with the control approach proposed in this paper. Also, the deterioration in the current loops response can be prevented, even if the power grids inductance increases. And, thus, low frequency disturbances can be prevented. The proposed control method is achieved with tuning-less corresponding to the power grids inductance.