Improved dimensionless nomograms approach in the electric drives and power electronics courses

摘要

Parameter estimation of the nonlinear electronic schemes, including inductances, capacitances, resistances, and switches represents a nontrivial problem in the "power electronics" and "electrical drives" courses. Difficulties could be observed during solutions of electrical circuits, which describe the behavior of electric motors in drives, and various electronic appliances are being used in power electronics. This situation is a result of complicated analytical approaches aiming to solve nonlinear ordinary differential equations describing the occurring processes. A typical student has a significant problem in attaining the analytical results. Various methods of linearization nonlinear elements permitting to obtain roughly analytical solutions and simplified solution were applied over the past. Nowadays, coarsely obtained results are not acceptable as a rule. As a result, smart simulation based on PSIM, MATLAB Simulink, and WOLFRAM Mathematica giving excellent opportunity for accurate answers are recommended. All software programs represent undoubtedly important and extremely accurate approaches. However, only numerical results are provided and are not capable of solution's generalization. It seems that in the Power Electronics and Electrical Drives courses, a wide submission could obtain methods of numerical nomograms with dimensionless representation of input-output parameters. Dimensionless approach allows significant diminishing of a number of decisive parameters and simplifies calculation, whereas keeping acceptable precision of results, as well as a possibility of outcome's generalization and representation variables trends in a wide range of input parameters. The likely objects of analysis may be, for example, output characteristics of DC motors fed by controllable and uncontrollable n-phase rectifiers, resistive rectifier losses and motor's efficiency, average and root mean square currents or voltages in electronic circuits, total harmonic distortion, and others. Long-time practice of these approaches approved their usefulness, productivity, and helpfulness.