Hideaki Hirahara

Maximum Efficiency Drives of Synchronous Reluctance Motors by a Novel Loss Minimization Controller With Inductance Estimator

This paper presents a method to maximize the driving efficiency of synchronous reluctance motors (SynRMs) having cross-magnetic saturation effects. A novel loss minimization controller that generates the optimum current vector is proposed. In the proposed controller, either an off- or online inductance estimator can be adopted. In both cases, the proposed controller can determine the optimum current vector quickly and automatically, and is capable of both maximizing the driving efficiency and also realizing high-precision torque control. In addition, when the proposed controller with the online inductance estimator is employed, a troublesome offline inductance measurement test is omissible. The validity of the proposed method is verified from simulation and experimental results on a 1.1-kW flux-barrier-type SynRM.

Universal Sensorless Vector Control of Induction and Permanent-Magnet Synchronous Motors Considering Equivalent Iron Loss Resistance

This paper presents a novel encoder-less vector control strategy which is universally applicable to both induction motors (IMs) and permanent-magnet synchronous motors (PMSMs). A fast rotor flux linkage phase estimator using stator flux linkage information obtained by a high-precision approximation voltage integral with error compensation is shown. Using this estimator, the authors construct a unified position/speed sensorless vector control algorithm taking equivalent iron loss resistance into account. All electrical motor parameters used for the control can be measured from unified off-line tests. The proposed universal sensorless vector control is implemented on a 0.4-kW squirrel-cage IM, a 0.4-kW interior PMSM with concentrated winding, and a 0.3-kW surface PMSM with distributed winding. Experimental results of several driving tests demonstrate the validity of the proposed.

A method to calculate the performance of linear induction motors using simple two-phase model

A new two-phase mathematical model of Linear Induction Motor (LIM) is discussed. This model is simpler than conventional model, but can correctly calculate both asymmetric primary current and thrust ripple performances. In addition, an improved DC testing method is proposed to determine all circuit parameters in the model. This test is completed by only one simple standstill test. Hence, both no-load steady-state operation and lock tests which are difficult to carry out on built-in LIMs are unnecessary. The proposed calculation method is implemented on a 3-phase, 4-pole and 12-slot single-sided LIM, and is validated by experimental and simulation results.

Universal sensorless vector control of induction and permanent magnet synchronous motors considering equivalent iron loss resistance

This paper presents a novel encoder-less vector control strategy which is universally applicable to both induction motors (IM) and permanent magnet synchronous motors (PMSM). A fast rotor flux linkage phase estimator using stator flux linkage information obtained by a high-precision approximation voltage integral with error compensation is shown. Using this estimator, the authors construct a unified position/speed sensorless vector control algorithm taking equivalent iron loss resistance into account. All electrical motor parameters used for the control can be measured from unified off-line tests. The proposed universal sensorless vector control is implemented on a 0.4 kW squirrel-cage IM and a 0.4 kW interior PMSM with concentrated winding. Experimental results of several driving tests demonstrate the validity of the proposed.

A simple method for determining equivalent circuit parameters of double-cage induction motors from no-load and locked-rotor tests

This paper presents a simple method to determine equivalent circuit parameters of double-cage Induction Motors (IM). A new formula to calculate the equivalent circuit parameters of double-cage IM is proposed. The formula is very simple so as to be able to calculate by a calculator but can determine the parameters of outer- and inner-cages bars accurately. In addition it is possible to take magnetic saturation effect of closed-slot rotor into account. Since all equivalent circuit parameters of double-cage IM can be determined only from classical no-load and locked-rotor tests, the proposed method is suitable for utilizing as a standardized testing method for double-cage IMs. The validity of the proposed method is demonstrated by experimental results on two 5.5kW-200V-4P-22A-50Hz double-cage IMs; one is an IM with semi-closed-slot rotor, the other is an IM with closed-slot rotor.

Universal sensorless vector control applicable to line-start permanent magnet synchronous motors with damper winding

This paper proposes an improved Universal Sensorless Vector (USV) control which can drive not only induction motor and damperless Permanent Magnet Synchronous Motor (PMSM) but also Line-Start PMSM with damper winding (LS-PMSM) by a unified control algorithm without a position/speed sensor. The reason why the step-out problem occurs when the conventional USV control is employed to operate the LS-PMSM is investigated and clarified. As a result, it is found that, by only adding a low pass filter to the load angle calculator to suppress the high-frequency vibration of the estimated load angle, the step-out problem is completely removed and the USV control becomes applicable to the LS-PMSM. The validity of the proposed method is demonstrated with experimental results on a 0.5-kW, 4-pole, 1500-r/min LS-PMSM.

Maximum efficiency drives of Synchronous Reluctance Motors with on-line stator resistance estimator

A maximum efficiency control of Synchronous Reluctance Motor (SynRM) using a novel on-line stator resistance estimator is presented. The proposed stator estimator entails utilizing the nature that stator resistance variation affects the accuracy of stator-flux-estimation-based inductance estimation values, but does not affect the selection of stator current vector in the maximum efficiency control system of SynRM. The proposed maximum efficiency control is implemented on a 1.1kW flux barrier type SynRM having cross-magnetic saturation effect. To correctly estimate the stator resistance and to improve the performance of the maximum efficiency control system in low speed are discussed with experimental verifications.