Petr Hutak

Maximum efficiency of an induction machine operating in a wide range of speed and torque - part 1 (theoretical analysis)

A set of unique equations usable to calculate directly the optimum slip frequency and line voltage of a 3phase squirrel-cage induction machine with respect to maximum efficiency is deduced in this article. An operation in steady state at any requested speed and torque in a wide range is taken into consideration. The proposed calculation is especially useful for independent traction purposes. The requested torque, speed and an extended mathematical model of the machine based on a Γ-network are the inputs of the calculation. The optimum slip frequency and line voltage are the outputs. The calculation results using the deduced analytical formulas were verified with a practical measurement and with a MATLAB simulation. Due to the extensiveness of the problems the correspondence of the theoretical calculation with the practical results will be presented in a separate 2nd part of the article.

High speed range field oriented control for permanent magnet synchronous motor

The paper deals with a synchronous motor control design. The field oriented control is assumed and it is suited for synchronous motor with permanent magnets. Current and voltage limitations are taken into account therefore a field weakening is used for reach high speed range with a most possible torque. A whole problem is solved using simulations in PC. Mathematical model of the synchronous motor is described in direct-quadrature reference frame. Basic electrical and mechanical equations taking into account partially saturations of magnetic circuits are used. Control methods with considered saturations, neglected saturations and without cross-coupling considering are compared.

Small electric vehicle drive control according to maximal efficiency criteria

This paper deals with induction drive control implementation according to the requirement of maximal efficiency for a traction application in a small electric car. Optimum setting of the motor slip frequency was found according to the criteria of maximal motor efficiency in a wide range of torque and speed (see [1] and [2]). The traction drive is an application without any extreme dynamic response requirement. It is possible to use scalar control strategies without any significant impact on the vehicle dynamic behavior. An implementation of the optimum motor setting into a scalar control is described in this article. Optimum rotor frequency and stator current look-up tables for any operating point in the used range of desired torque and actual speed were generated and used in common induction machine scalar control schemes.

Maximum efficiency of an induction machine operating in a wide range of speed and torque - part 2 (calculation, simulation and measurement results)

A set of equations usable to calculate directly the optimum slip frequency and line voltage of a 3phase squirrel-cage induction machine with respect to maximum efficiency was deduced in part 1 of this article. An operation in steady state at any requested speed and torque in a wide range is taken into consideration. The requested torque, speed and an extended mathematical model of the machine based on a Γ-network are the inputs of the calculation. The optimum slip frequency and line voltage are the outputs. The calculation results using the deduced analytical formulas are compared with practical measurement results and with a MATLAB simulation of the machine input power in this part 2 of the article.

Speed Estimator for Low Speed PMSM Aerospace Application

The paper is focused on development of low speed PMSM direct drive application. The high resolution of position setting (18 bits per revolution) is demanded at very low speed about 10 RPM. The quantization of speed controller error cause unaccepted torque ripple. The digital filters reduce dynamic of speed control loop therefore, the speed estimator has to be employed to reduce torque ripples without reduction of speed control performance. The application is intended for demanded aerospace application. The paper describes design of speed estimator with cooperation of vector controlled PMSM motor. The Simulink model is realized to verify the proper operation of whole drive application and simulation results are presented in this paper.

Induction Machine Models and Equivalent Circuits Based on Hybrid Parameters of Two-Port Network

The paper is focused on development of induction machine (IM) model based on general two-port network theory, which is elemental theory well-known for all electrical engineers. Since the theory of IM is more specialized and known for engineers with some expertise in the field of electrical machines and drives. Application of the two-port network theory on IM can clarify the development process of IM model or eventually equivalent circuit for wide area of electrical engineers. The whole building process is also based on analogy with transformer and the theory of rotational coordinates is also employed. The models and equivalent circuits are then more suitable for understanding physical principles of IM from macroscopic point of view.

Drive and control system for TAH application

The paper presents analytic design of active magnetic bearing PM synchronous motor for TAH (Total Artificial Heart) application and description of the drive and levitation electromagnet control. Pump system is double ventricle blood pump consisting of slotless PM axial flux synchronous machine and magnetic active bearings. The general electric machine theory is applied to the motor design. Power quality is ensured by the help of the rare earth PM and for good torque quality is used slotless, three phase winding and surface mounting PM. Control part deals with the synchronous motor and magnetic bearing control. Two structures, voltage and current, were design and tested for the position regulation. Mathematical model was successfully simulated. On the base of this model the regulation structure for positional feedback control was design. Design of the regulators is based on the mathematical model description of controlled system.