Here, the authors present a model order reduction (MOR) framework based on singular perturbation approximation to accelerate the simulation of high-fidelity power electronic converters. The problem of slow simulation speeds caused due to the wide span of the eigenvalues is mitigated by implementing the proposed framework. The dynamics of the original stiff system is approximated by neglecting the transient contribution of the non-dominant eigenvalues and retaining the steady-state contribution of all the eigenvalues of the system. The model reduction problem has been reformulated to fit the switched nature of these circuits. An error bound for the approximation method has been derived. The method is demonstrated on a DC-DC boost converter and a Class-E amplifier. Significant improvement in speed and reduction in the size of the solution arrays is achieved. It is seen that the reduced-order models are able to replicate the response of the original models and the approximation error is within acceptable limits.

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MATLAB / SIMULINK implementation of the Direct Torque Control Scheme for induction motors is presented in this paper. Direct Torque Control (DTC) is an advanced control technique with fast and dynamic torque response. The scheme is intuitive and easy to understand as a modular approach is followed. A comparison between the computed and the reference values of the stator flux and electromagnetic torque is performed. The digital outputs of the comparators are fed to hysteresis type controllers. To limit the flux and torque within a predefined band, the hysteresis controllers generate the necessary control signals. The knowledge about the two hysteresis controller outputs along with the location of the stator flux space vector in a two dimensional complex plane determines the state of the Voltage Source Inverter (VSI). The output of the VSI is fed to the induction motor model.A flux optimization algorithm is added to the scheme to achieve maximum efficiency. The output torque and flux of the machine in the two schemes are presented and compared.