1,720,988 research outputs found
Mild-hybrid traction system based on a bidirectional half-bridge interleaved converter and a three-level active NPC inverter-fed PMSM
No full textSelf-Commissioning and Compensation of Phase Error in Low-Cost Voltage Sensing for Vienna Rectifiers and Other Grid-Tied Converters
No full textControl of unidirectional three-phase Vienna rectifier as Power Factor Corrector is relatively simple in the Continuous Conduction Mode. However, peculiar issues arise in the transition to Discontinuous Conduction Mode, resulting in lower regulation performance (e.g. higher Total Harmonic Distortion). To solve this problem, open-loop current control techniques have been recently proposed, which strongly rely on the voltage sensing for achieving accurate control of input current. Moreover, the phase of grid voltage needs to be known with high accuracy, for imposing the correct power factor. In this paper, the effects of poor voltage sensing (e.g. when using a low-cost transformer) on the current distortion and on Power Factor are considered. In order to overcome these issues, while keeping the cost low, a phase-shift compensation method is proposed in this paper, which is based on a simple digital filter. Also, the most important parameter of the transformer transfer function is identified by means of a self-commissioning procedure, which requires no additional hardware and can be easily carried out in the field. Selected simulation and experimental results are reported to validate the proposal. It is worth to mention that the proposal may be applied also to other topologies, i.e. virtually to any grid-tied converter
Adaptive Flux-Weakening Controller for Interior Permanent Magnet Synchronous Motor Drives
No full textVoltage 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
Optimal Voltage Feed-Back Flux-Weakening Control of IPMSM
No full textA voltage feed-back flux-weakening (FW) control scheme for vector-controlled Interior Permanent Magnet Synchronous Motor (IPMSM) drive 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 overall dynamics of the voltage control loop is carried out, also taking into account non-linear effects and discrete-time implementation issues. The design of the controller can therefore be optimized for each operating condition, allowing to fix stability properties and to maximize bandwidth of the loop. A simple but effective scheduling of the voltage controller gains is proposed to address this. Maximization of the dynamical performance provides the main advantage of the proposed approach, i.e. 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
Design issues and estimation errors analysis of back-EMF based position and speed observer for SPM synchronous motors
No full textA back-electromotive force (back-EMF) based sensorless technique for surface-mounted permanent magnet synchronous motor (SPMSM) drive systems 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-state representation. This allows a more intuitive but equivalent design of the observer's gains, based on the standard frequency response, as compared to eigenvalues analysis. Moreover steady-state errors are obtained from a theoretical point-of-view, including the effects of the most common non-idealities affecting the drive system (e.g. offsets) and parameters sensitivity. Full simulation and experimental characterization of the sensor-less drive is provided with reference to a general purpose industrial drive, i.e. both in transient and steady-state conditions and in the whole speed/torque operating range
Sensorless quasi-standstill and very low-speed position detection in non-salient PMSMs based on current injection and back-EMF observer
No full textAccuracy and robustness of sensorless speed control of non-salient PMSMs in the low-speed region and at start-up is a critical issue, due to the low amplitude of the back-EMF which prevents estimation and then closed-loop control in the zero speed range. This problem is usually overcome by adopting an open-loop control (e.g. constant amplitude rotating current space vector), which is normally able to start the motor up to an enough high speed, where sensorless closed-loop control is possible. Open-loop startup is however not robust against load torque and inertia variations and random initial rotor position conditions. Also the extension of the closed-loop operating range towards zero is strongly desired. Standard techniques relying on magnetic saliency are not applicable (i.e. no relevant anisotropy is present in the considered machine), and some methods based on the detection of torque production by signal injection can be adopted. The methods proposed and studied in this paper belongs to this last class. Two different application cases will be considered: an initial high-accuracy position detection at quasistandstill and a position and speed tracking for closed-loop sensorless speed control. A complete theoretical analysis is reported to demonstrate the features of the proposal and highlight the dependence on certain design parameters. Then extensive simulation and experimental investigations based on an industrial drive system are included to prove the feasibility of the method and validity of the theoretical analysis
Adaptive Flux-Weakening Controller for IPMSM Drives
No full textVoltage feed-back flux-weakening (FW) control scheme for vector-controlled Interior Permanent Magnet Synchronous Motor (IPMSM) 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 overall dynamics of the voltage control loop is carried out, also taking into account non-linear effects and discrete-time implementation issues. 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 performance provides the main advantage of the proposal, i.e. 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
Design Issues and Estimation Errors Analysis of Back-EMF Based Position and Speed Observer for SPM Synchronous Motors
No full textA 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. © 2014 IEEE
Sensorless Control for IPMSM using PWM Excitation: Analytical Developments, Implementation Issues
No full textPersistent, transient and, very recently, pulse width modulated voltage excitation are employed to track saliency of IPM machines, aiming at estimating rotor position. In this paper current transient response introduced by standard (or slightly modified) PWM excitation is considered and analytical relationship between phase current derivatives, inductance and rotor position is derived. A complete mathematical model is developed in the case of IPM machine, by taking also into account the dependence of the rotor position estimation error on the mutual inductance, which is neglected in the past literature adopting the same sensorless approach. Estimation is performed within a single PWM period, differently from previous approaches. Measurement of current derivatives is obtained from dedicated Rogowski coils, oversampling and real-time processing of the measured values. Acquisition issues due to short application times of voltage vector (e.g. during zero and low speed operations) have been overcome by means of a proper edge-shifting technique on the PWM signals. A motor drive system for fractional power high speed IPM motor is considered as a test bench to prove the effectiveness of the proposal
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