Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

CONTROLLING AN AC MOTOR WITH CHANGING OPTIMIZATION

IP.com Disclosure Number: IPCOM000009669D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-10
Document File: 2 page(s) / 78K

Publishing Venue

Motorola

Related People

Radim Visinka: AUTHOR [+2]

Abstract

The proposal relates to controlling an AC elec- tric motor (cf. figure), for example starter/generator for a combustion engine. The stator frequency is determined by adding an optimal slip frequency of the motor to the desired rotational frequency of the rotor. The stator voltage is related to the difference between actual rotational frequency and desired rotational frequency of the rotor. A pulse width modulation unit receiving the desired stator frequen- cy and voltage controls an inverter to supply the appropriate coil voltages to the motor.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 56% of the total text.

Page 1 of 2

0 M M-LA Technical Developments

 CONTROLLING AN AC MOTOR WITH CHANGING OPTIMIZATION

by Radim Visinka and Leos Chalupa

INTRODUCTION

  The proposal relates to controlling an AC elec- tric motor (cf. figure), for example starter/generator for a combustion engine. The stator frequency is determined by adding an optimal slip frequency of the motor to the desired rotational frequency of the rotor. The stator voltage is related to the difference between actual rotational frequency and desired rotational frequency of the rotor. A pulse width modulation unit receiving the desired stator frequen- cy and voltage controls an inverter to supply the appropriate coil voltages to the motor.

PROBLEM

  Since motors have changing load conditions (for example start-up vs. running at rated speed), adding a constant slip frequency might sometimes not be desired.

SOLUTION

  A block diagram (Figure 1) shows a preferred implementation of the proposal. Motor 20 (stator 2 1, rotor 22) receives power from inverter 26 which is controlled by pulse width modulation unit 33. Microcontroller 50 receives an input signal corre-

sponding to the desired rotational frequency of rotor 22 via line 34 and receives a signal corresponding to the actual rotational frequency of the rotor 22 (gen- erated by tacho generator 38 and subtracted from the

input signal received via input line 34 by circuit 40). Filter 42 filters the resulting differential signal (out- put circuit 40).

  The resulting signal (line 44) is rep...