Phase voltage measuring device of an AC motor and a measuring method thereof

• US 5,268,628 A
• Filed: 10/21/1992
• Issued: 12/07/1993
• Est. Priority Date: 10/21/1991
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Dong-Il, Kim
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US07/964,064
• Time in Patent Office: 412 Days
• Field of Search: 318/731, 318/732, 318/733, 318/734, 318/735, 318/767, 318/808, 318/809, 318/810, 318/811, 318/812
• US Class Current: 318/809
• CPC Class Codes: H02P 21/141 Flux estimation

Abstract

A phase voltage measuring device for an alternating current and a measuring method thereof for detecting a voltage from a main power supply Vcc supplied to a motor, wherein the voltage is converted to a digital signal which is multiplied by a basic pulse width modulation signal for detection of the phase voltage. A phase voltage measuring device and a measuring method have the advantage of measuring a phase voltage with a simple circuit by eliminating the problems associated with a conventional phase voltage measuring device which uses a current measuring coil and a pulse converter.

Claims

1. A phase voltage measuring method for an alternating current motor having a motor drive means controlled by pulse width modulated signals, comprising the steps of:

detecting the voltage of a main power supply supplied to the motor drive means;

converting the detected voltage of the main power supply to digital values;

cutting off the main power supply in response to the digital values; and

generating phase voltages by multiplying the pulse width modulated signals with the digital values.

2. A phase voltage measuring device for an alternating current motor having a motor drive means comprising:

means for generating pulse width modulation signals;

means connected to said generating means for distributing the pulse width modulation signals;

motor driving control means, responsive to the distributed pulse width modulated signals, for supplying pulse width modulated signals to the motor drive means of the alternating current motor;

means for detecting the voltage of the main power supply supplied to the motor drive means;

analog-to-digital converting means for converting the detected voltage of the main power supply to digital values;

power cut-off means, responsive to the digital values from the analog-to-digital converting means, for cutting off the main power supply; and

multiplying digital-to-analog converting means for generating phase voltages by multiplying the pulse width modulated signals with the digital values from the analog-to-digital converting means.

3. A phase voltage measuring device according to claim 2 which further includes noise elimination means for eliminating noises in the voltages detected in the main power supply.

4. A phase voltage measuring device according to claim 3 wherein the power cut off means includes photocouplers.