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This paper presents a comprehensive evaluation of several direct torque control (DTC) strategies for permanent magnet synchronous machines (PMSMs), namely DTC, model predictive DTC, and duty ratio modulated DTC. Moreover, field-oriented control is also included in this study. The aforementioned control strategies are reviewed and their control performances are analyzed and compared. The comparison is carried out through simulation, finite-element analysis, and experimental results of a PMSM fed by a two-level voltage source inverter. With the intent to fully reveal the advantages and disadvantages of each control strategy, critical evaluation has been conducted on the basis of several criteria: Torque ripple, stator flux ripple, switching frequency of inverter, steady-state control performance, dynamic response, machine losses, parameter sensitivity, algorithm complexity, and stator current total harmonic distortion. [ABSTRACT FROM PUBLISHER]

This paper introduces a detailed nonlinearity characterization technique for insulated-gate bipolar transistor inverters in a drive system which is able to measure device nonlinearities. Methods are derived from measurements of the voltage on the inverter phases. These measurements are obtained while applying a set of direct currents to an electrical machine. These methods are then applied to tests using alternating current. The study of inverter nonlinearities is useful in order to conduct condition monitoring. These methods fulfill the need to characterize each device in an inverter. In addition to characterizing every device using either ac or dc current, the method is resistant to noise; for these reasons, the method is applicable in the field. Simulations and experimental work demonstrate the benefits and applicability of the methods. [ABSTRACT FROM AUTHOR]

In this paper, the effectiveness of a simplified characterization method for permanent magnet machines is evaluated through performance sensitivity analysis. Performance sensitivity analysis is a novel way to evaluate the effectiveness of any identification method, as it investigates the effects of parametric errors upon the output performance of a machine. Parametric errors are due to inaccuracies during the identification process. This evaluation tool was validated using a 10-kW SmCo interior permanent magnet machine characterized using two different identification methods. A detailed identification procedure is used as the basis for evaluating a simplified method. The performance experimental data were collected using torque controllers based on the parameters extracted with both approaches. This information is used to perform the sensitivity analysis over the operating range of the machine. Finally, the results are compared and analyzed to determine the effectiveness of the simplified characterization method and its implications on the control performance. [ABSTRACT FROM AUTHOR]