Search

Frequency analysis of processes in the frequency-controlled induction motor drive s, as in automatic control systems with dynamic non-linearities, are presented in this paper. For the first time, the dynamic transfer function in terms of electromagnetic torque (m) from absolute slip determined by the load and frequency of the supply voltage are proposed. To study the dynamic characteristics, a method for constructing a family of frequency characteristics for fixed values of absolute slipss and frequencies of the supply voltage are described. The frequency characteristics corresponding to these transfer functions are constructed in the Simulink application of the MatLab software. Based on results of the analysis the structural correction methods that improve the dynamics of such nonlinear systems are proposed. This paper is an example of how the initial complicated (but more accurate) interpretation of nonlinearity allowed us to find a new best solution to the problem of controlling a complex dynamic object.

This paper presents the implementation of a crossquad circuit suitable for low-voltage operation. The proposed cell exploits a dynamic positive feedback gm boosting technique to achieve linear voltage-to-current conversion, while it manages to work with low-voltage with no extra bias current and minimal additional hardware. Results for a 0.5 m CMOS implementation supplied at 3 V show a 0.972 % voltage-tocurrent accuracy, improving the 0.867 % accuracy of a previously reported cross-quad topology also suitable for lowvoltage operation which is based on folded transistors. Ministerio de Ciencia e Innovación (PET2007-00336, PET2008-0021) Agencia Española de Cooperación Internacional para el desarrollo - Programa de Cooperación Interuniversitaria e Investigación Científica (AECI-PCI) (A/018704/08) Universidad de Zaragoza (UZ2008-TEC-08)