Motor characterization has a fundamental role in dynamics, torque accuracy, and efficiency of vector controlled Synchronous Reluctance Machine (SynRM) drives. Control performances and robustness in the whole speed/torque range, including the flux-weakening region, and in sensorless operation strongly rely on the knowledge of machine flux versus current characteristics. A convenient flux saturation approximating function is proposed in this paper, together with an efficient parameters self-identification procedure. The adopted strategy is very simple and can be performed at stand-still by injecting a proper voltage stimulus (current control is not involved), and does not require any additional hardware (motor can be either connected or disconnected from mechanical load). Nevertheless, an excellent fitting for the flux curves on both axes is obtained, using reasonable memory and computational resources. These features make the technique very suitable to motor self-identification in industrial drives. Experimental results based on a commercial drive and two SynRMs are reported to demonstrate the effectiveness of the proposal. Extensions of the method to the evaluation of the whole flux map (including cross-saturation effects) or to interior permanent-magnet machines is also investigated and verified. © 2016 IEEE

Voltage feedback flux-weakening control scheme for vector-controlled interior permanent magnet synchronous motor drive systems is considered in this paper. The voltage controller is based on the difference between the amplitude of the reference voltage space vector and a proper limit value, related to the feeding inverter limitations, and adopts the phase angle of reference current space vector as the control variable. A novel theoretical analysis of the dynamics of the voltage control loop is carried out by considering nonlinear effects and discrete-time implementation issues as well. The design of the controller can therefore be optimized for each operating condition by an adaptive approach, allowing to define stability properties and to maximize bandwidth of the voltage control loop. Maximization of the dynamical performances provides the main advantage of the proposal, that is, allows a lower voltage (control) margin to be considered with respect to standard approaches, leading to a higher torque and system efficiency and/or a reduced value of the dc bus capacitance. A motor drive system for home appliances is considered as a test bench to prove the effectiveness and importance of the proposal. © 2014 IEEE

A back-electromotive force-based sensorless technique for surface-mounted permanent magnet synchronous motor drives is considered in this paper. The model of the observer is developed in the Laplace domain and represents an original approach with respect to state-of-art proposals, normally employing a state-space representation. This allows a more intuitive but equivalent design of the observer's gains, based on the standard frequency response, as compared with eigenvalues analysis. Moreover steady-state errors are obtained from a theoretical point-of-view, including the effects of the most common nonidealities affecting the drive system and parameters sensitivity. Full simulation and experimental characterization of the sensorless drive is provided with reference to a general purpose industrial drive, i.e., both in transient and steady-state and in the most meaningful speed/torque operating conditions

Dead-time and switch voltage drops represent the most important sources of distortion of the (average) output voltage in pulsewidth modulation inverters. Their effect is a function of the parameters of the drive system and of the operating conditions and is often intolerable in many drives applications, thus requiring a proper compensation strategy. Many techniques are implemented in industrial drives and reported in the literature, even very recently. Differently from standard approaches, the proposed methodology is based on a detailed physical model of the power converter (including output capacitance), described by a small set of parameters. A novel self-commissioning identification procedure is introduced, adopting multiple linear regression. The technique is tested on a commercial drive in comparison with state-of-the-art techniques. In addition, back electromotive force estimation improvements in a permanent-magnet synchronous motor sensorless drive system are shown to provide additional validation of the method. © 1972-2012 IEEE

In this paper, a sensorless controller for an interior permanent-magnet synchronous motor is presented based on well-known high-frequency signal injection techniques. The issue of the demodulation process is the key point of this paper. A novel approach based on discrete Fourier transform and nonconventional reference frame transformation is presented, allowing a simple and robust noncoherent demodulation, i.e., in which no information about the carrier phase is needed. In the classically adopted coherent approaches, in fact, uncertainty about carrier phase reflects in uncertainty in the demodulated signal amplitude, affecting observer gains and signal-to-noise ratio and definitively providing a degradation of the performance of the estimator. Analytical development of the sensorless algorithm, including the demodulation technique, is provided. A complete investigation by simulation is carried out aiming at showing the performance of the proposed method. Finally, experimental results are presented based on a prototype motor drive for city scooters

Analytical design and adaptation of voltage regulation loop for flux-weakening control of Interior Permanent Magnet Synchronous Motor drives are addressed in this paper. Theoretical analysis of the overall dynamics of the loop has been carried out in recent papers, also taking into account non-linear effects and discrete-time implementation issues. A proper gain adaptation technique was proposed to provide a local linearization, aiming at maximization of the dynamical performance and maintain stability of the loop. Unfortunately no closed-form design method was provided due to the complexity of the transfer function and only graphical analysis of the loop function was shown. In this paper a novel simplified analysis is proposed, which allows analytical design of the regulator gains after the application of a real-time compensation of any non-linearity. Simulations validate the approach, and experimental tests show the feasibility of the technique on a standard drive hardware, leveraging its ease of implementation

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