Masayuki Sanada

Wide-speed operation of interior permanent magnet synchronous motors with high-performance current regulator

Interior permanent magnet synchronous motors can be applied to applications requiring wide-speed operation. The current vector control algorithm of an interior permanent magnet synchronous (IPM) motor for constant power operation over the base speed is proposed. As the available voltage controlling the armature current vector is small in the flux-weakening constant power region, the current vector sometimes becomes uncontrollable in transient operations because of the current regulator saturation. The high-performance current regulator is also proposed to improve the current responses in the flux-weakening region, which includes the decoupling current controller and the voltage command compensator. The control performances are confirmed by several drive tests with respect to the prototype IPM motor. >

Sensorless control strategy for salient-pole PMSM based on extended EMF in rotating reference frame

This paper presents a novel sensorless control strategy for a salient-pole permanent magnet synchronous motor. A new model of salient-pole PMSM using an extended electromotive force (EMF) in the rotating reference frame is utilized to estimate both position and speed. The extended EMF is estimated by a least-order observer, and the estimation position error are obtained from the extended EMF. Both estimated position and speed are corrected so that the position error becomes zero. The proposed system is very simple and the design procedure is easy and clear. Several experimental drive tests are demonstrated and the experimental results show the effectiveness of the proposed sensorless control system.

Sensorless output maximization control for variable-speed wind generation system using IPMSG

This paper proposes a variable-speed wind generation system using an interior permanent-magnet synchronous generator (IPMSG). The armature current vector of the IPMSG is optimally controlled according to the generator speed in order to maximize the generated power from the wind turbine. The IPMSG is controlled by the loss-minimization control with maximum power point tracking below the base speed, which corresponds to low and medium wind speed, and the maximum energy can be captured from the wind. Above the base speed corresponding to the high wind speed region, the current- and voltage-limited maximum output control is applied, where the current vector is optimally controlled so that the output may become the maximum in consideration of the constraints of current and voltage. The proposed output maximization control is achieved without mechanical sensors such as wind speed sensor and position sensor. The control system has been developed and several experimental results show the effectiveness of the proposed wind generation system.

Effects and Compensation of Magnetic Saturation in Flux-Weakening Controlled Permanent Magnet Synchronous Motor Drives

Permanent magnet synchronous (PM) motors can be applied to applications requiring constant power operation, such as traction and spindle drives by means of flux-weakening control. In a PM motor drive system with flux-weakening control, the motor parameters are used to produce the current vector command. The motor parameters vary because of magnetic saturation and as a result, the control performances are affected by the magnetic saturation. In this paper, the effects of magnetic saturation are examined and the control system considering the magnetic saturation is proposed. The performances of the proposed control system are examined by simulations and the experimental results with respect to the prototype interior permanent magnet synchronous motor

Mechanical Sensorless Drives of IPMSM With Online Parameter Identification

A mechanical sensorless drive system for an interior permanent-magnet synchronous motor, for which parameters including the inverter are identified, is proposed in this paper. The rotor position is estimated by a signal-injection sensorless scheme at standstill. The resistance, including the on-resistance of the insulated-gate bipolar transistor, the voltage error caused by the dead time of the inverter, and the d-axis and q-axis inductances are identified at standstill using the estimated position. After the motor starts by the signal-injection sensorless control, the sensorless scheme changes to a scheme based on the extended electromotive force estimation, which uses the identified parameters. The magnet flux linkage is also identified under the sensorless operation. The effectiveness of the proposed method is verified by several experimental results

Optimum control of IPMSG for wind generation system

This paper presents the optimum control of an interior permanent magnet synchronous generator (IPMSG) for a wind generation system. In order to maximize a generated power, IPMSG is controlled by a maximum power point tracking (MPPT) control and a maximum efficiency control. The torque of IPMSG is suitably controlled according to a generator speed and thus the power from a wind turbine settles down on the maximum power point by the proposed MPPT control without a wind speed detector. Moreover, using the maximum-efficiency control and the maximum-torque control, the losses of IPMSG are minimized and as a result the maximum generated power is obtained. Experimental results show the effectiveness of the proposed control method.

Sinusoidal current drive system of permanent magnet synchronous motor with low resolution position sensor

The high performance drives of the sinusoidal back-EMF type permanent magnet synchronous motor can be achieved by the current vector control, where the sinusoidal currents flow according to the rotor position and the current phase is suitably controlled according to the operating condition. In such a high performance drive system, a high resolution position sensor is desired. In this paper, a sinusoidal current drive system with a low resolution position sensor is proposed. The high resolution position information is obtained by the position estimating circuit from the signal of a low resolution position sensor. The steady-state and transient characteristics are examined by several experiments, then it is confirmed that the sinusoidal current drive and the high performance current vector control can be achieved by the proposed drive system.

Performance Evaluation of a High-Power-Density PMASynRM With Ferrite Magnets

Although motors that use rare-earth permanent magnets (PMs) typically exhibit high performance, high costs and concerns about the stability of raw material supplies are leading to their decreased production. However, the performance of such motors is not easily matched without the use of rare-earth PMs. This paper proposes and examines a PM-assisted synchronous reluctance motor with ferrite magnets that has the same power density as rare-earth PM synchronous motors. A suitable rotor structure for high torque and high power is discussed with respect to the demagnetization of ferrite magnets and the mechanical strength.

Performance of PM assisted synchronous reluctance motor for high efficiency and wide constant power operation

This paper examines the design and the performances of a permanent magnet assisted synchronous reluctance motor (PMASRM) for a wide constant-power operation. The effects of properly adding magnets into the rotor of a synchronous reluctance motor are examined by the several experimental results and analyses on the prototype machines. The proposed machine can offer a large constant-power speed range, high-efficiency and high-power-factor operation in comparison to the complete synchronous reluctance motor. It was shown that the problems such as the decrease of efficiency at light-loads and the uncontrolled generator mode operation, which occur in the high-speed flux-weakening operation of the conventional PM motor drives, can be eliminated in the PM assisted synchronous reluctance motor.

Prediction of iron loss in rotating machines with rotational loss included

Iron loss prediction is an important issue in both design and analysis of electrical machines. Because of their complicated structure, flux distribution, and rotational variation of flux, it is difficult to predict the iron loss in a machine exactly. This paper studies the iron loss in the core of rotating machines in which the rotational field is dominant, using the finite-element method. For electrical machines in practical operation, additional iron losses due to the appearance of rotation of flux vectors and harmonic flux densities make the calculation results deviate from the measured data. We have revised the method to account for these excess iron losses by considering both the influences of flux vector rotations and flux density harmonics. Calculation and experiments on two kinds of interior permanent-magnet synchronous motors have verified that our method produces results that agree well with the experimental ones.