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This paper proposes a new sensorless vector control method for energy-efficient and wide-speed-range drives of permanent-magnet synchronous motors. The proposed sensorless method has the following features: 1) wide-speed-range drive under voltage limit; 2) current limitation; and 3) high efficiency. These features are realized in a very simple manner and can operate adaptively in all sensorless driving modes, including motoring/regenerating and steady/transient states. The usefulness of the proposed method is verified by extensive experiments. [ABSTRACT FROM PUBLISHER]

The phase, frequency, and amplitude of single-phase voltages are the most important and basic information required for single-phase microgrid connected applications. This paper proposes a new “D-estimation method” for instantly estimating the phase, frequency, and amplitude of frequency-varying single-phase signals in such applications. The D-estimation method has the following attractive features: 1) it is a new filtering method using the D-filters; 2) it involves the use of only filters and can be easily designed; 3) it is inherently stable and robust in hostile envelopments caused by a frequency variation, a phase jump, amplitude sag/swell, harmonic distortion, and/or contaminated noise; 4) even in the hostile envelopments, good instant estimates of the phase, frequency, and amplitude can be obtained; 5) it is simple, but can exhibit fast-tracking performance comparable to the “robust PLL method.” This paper presents the D-estimation method together with the design rules in detail; the usefulness of the method is verified by performing extensive numerical experiments. [ABSTRACT FROM AUTHOR]

This paper proposes a new sensorless vector control method for salient-pole permanent-magnet synchronous motors. With regard to phase estimation, the sensorless vector control method is featured by a new high-frequency voltage injection method (i.e., carrier modulation method), which is distinguished from the conventional ones by a unique ellipse shape of spatially rotating high-frequency voltage, and by a new phase-locked-loop method as a demodulation method whose input is a high-frequency current component multiplied signal. The new vector control method established by two innovative technologies for modulation! demodulation can have the following high-performance and at- tractive characteristics. 1) It can allow 250% rated torque at standstill. 2) It can operate from zero to the rated speed under the rated motoring or regenerating load. 3) It accepts instant injection of the rated load even for zero-speed control. 4) Phase estimation is robust against inverter dead time, and proper phase estimate can be obtained even under circumstances where stator current crosses the zero at high frequency. 5) Computational load for estimating rotor phase is very small. Usefulness of the proposed new vector control method is verified through extensive experiments. [ABSTRACT FROM AUTHOR]

Phase, frequency, and amplitude of single-phase voltages are the most important and basic information required for single-phase grid-connected applications. This paper proposes a method for instantly and robustly estimating the phase, frequency, and amplitude of frequency-varying single-phase signals for such applications, which is a phase-locked loop (PLL) method based on a structure. The proposed method has the following attractive features: 1) the estimation system results in a nonlinear system, but it can be stabilized; 2) all subsystems constructing the system can be easily designed; 3) "two-phase signal generator" can autotune a single system parameter in response to varying frequency of the injected signal; 4) high-order "PLL-Controllers" allowing fast tracking can be stably used; and 5) even in hostile envelopments, favorable instant estimates can be obtained. This paper proposes the estimation method and verifies its usefulness by extensive numerical experiments. [ABSTRACT FROM AUTHOR]

This paper proposes new practical optimal current control methods for a newly emerging class of synchronous motors with hybrid rotor fields by both permanent magnet and winding. In a practical situation with limited voltage, the extensively used permanent-magnet synchronous motor hardly achieves an ideal performance in an energy-efficient manner due to its constant magnet field, which simultaneously allows both low-speed high-torque and wide speed-range operations. The hybrid-field synchronous motors (HFSMs) are potential candidates that can achieve the ideal performance as practical motors with control- lable hybrid rotor field. HFSMs can dynamically control the rotor flux according to the operation requirements by the low-speed, high-torque, and wide speed-range operations, etc. For the HFSMs, the same torque can be produced by a variety of stator and rotor currents due to the nonlinearity between the torque and the currents. Produced losses and required voltages depend upon the associated currents. Consequently, in the situation that current control systems are well constructed, appropriate determination of a set of stator and rotor current commands plays a key role to achieve the ideal performance in an energy-efficient manner. The proposed methods determine the current commands corresponding to a given torque command such that the total winding copper losses due to the stator and rotor currents can be minimized if the exact currents associated with the torque command exist; the best approximate torque can be produced if no exact associated currents exist, which is, of course, under the circumstance of a voltage limitation. The determined current commands are optimal in the sense of energy efficiency or degree of approximation under voltage limitation. New recursive algorithms searching the optimal current solution in real-time are also given as parts of the methods. The proposed methods are analytical but practical, whose usefulness is verified through experiments. [ABSTRACT FROM AUTHOR]

This paper proposes a new sensorless vector control method that can be applied to both of salient-pole and non-salient-pole permanent-magnet synchronous motors (PMSMs). The proposed method estimates the phase of a rotor flux by a newly developed state observer in a stationary reference frame for sensorless vector controls of PMSMs. The flux state observer has the following attractive features: 1) it requires no steady-state conditions for the dynamic mathematical model of the motor; 2) its order is the minimum second; 3) a single observer gain is simply constant over a wide operating range and can be easily designed; 4) it utilizes motor parameters in a very simple manner; and 5) its structure is very simple and can be realized at a very low computational load. The proposed speed-estimation method, which exploits the inherent physical relation of integration/derivation between phase and speed, is very simple and can properly estimate rotor speed. The usefulness of the proposed method is examined and confirmed through extensive experiments. [ABSTRACT FROM AUTHOR]

This paper proposes a new sensorless vector control method that can be applied to both salient-pole and nonsalient-pole permanent-magnet synchronous motors (PMSMs). The proposed method estimates phase of rotor flux by a newly developed flux-state observer for sensorless vector control of PMSMs, which is referred to as the "D-state observer." The D-state observer has the following attractive features: 1) it requires no additional steady-state condition for the motor mathematical model; 2) its order is the minimum second; 3) a single observer gain is simply constant over a wide operating range, and easily designed; 4) it utilizes motor parameters in a very simple manner; and 5) its structure is very simple and can be realized at a very low computational toad. Usefulness of the proposed method is examined and confirmed through extensive experiments. [ABSTRACT FROM AUTHOR]

Proposes an nth order two-input/output filter in D-module for two-phase signal processing. Applications of the rotator-accompanied filter; Characteristics of matrix factor for module; Definition of filter in D-module; Realizations of module filter.