Motor controller

• US 6,700,343 B2
• Filed: 08/09/2002
• Issued: 03/02/2004
• Est. Priority Date: 07/24/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kaneko, Satoru, Masaki, Ryoso, Sakurai, Yoshimi
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US10/214,728
• Publication Number:
  US 20030020429A1
• Time in Patent Office: 571 Days
• Field of Search: 318/138, 318/254, 318/439, 318/434, 318/700, 318/720-724
• US Class Current: 318/434
• CPC Class Codes: H02P 6/18 without separate position detecting elements

Abstract

In order to propose an inexpensive and highly precise motor controller, it is structured so as to detect the position of the rotor on the basis of the difference between the real current differential vector and the reference current differential vector, thereby control the motor without using a rotation position sensor.

Claims

1. A motor control apparatus comprising:

an AC motor,

a power conversion device for adding a voltage to said AC motor according to a pulse width modulation signal generated by comparing an order value with a carrier wave,

a control device for controlling said order value by detecting a position of a rotator of said AC motor based on a differential between an actual current differential vector and a reference current differential vector, and

a current sensor abnormality detector for outputting a current sensor abnormality signal value by judging whether a sum of said respective electric current differential values calculated by detecting an electric current from each phase of said AC motor and by detecting an electric current differential value, is more than a predetermined value or not.

2. A motor control apparatus comprising:

an AC motor,

a power conversion device for adding a voltage to said AC motor according to a pulse width modulation signal generated by comparing an order value with a carrier wave,

a current sensor abnormality detector for outputting a current sensor abnormality signal value by judging whether a sum of said respective electric current differential values calculated by detecting an electric current from each phase of said AC motor and by detecting an electric current differential value, is more than a predetermined value or not,

a first phase current detection part for detecting respective said electric current differential values which change according to each voltage vector added by plural interval,

a standard phase current difference operation part for operating a standard phase current difference obtained by difference of plural said voltage vectors, and

a position detection part for detecting a rotator position of said AC motor using said electric current difference and said standard phase current difference, said motor control apparatus characterized by further comprising;

a control device for controlling said voltage order value by detecting said rotator position of said AC motor and for controlling said AC motor including said current sensor abnormally signal value.

3. A motor control apparatus as defined in claim 2, wherein said first phase current detection part has a function to remove a DC component.

4. A motor control apparatus as defined in claim 2, comprising:

a second phase current detection part for detecting a phase currents of two phases which is different from that detected by said first phase current detection part,

wherein said phase current is controlled based on output of said second phase current detection part.

5. A motor control apparatus as defined in claim 4, said control device comprises abnormality detection part for detecting an abnormality of said first or second phase current detection part based on an alternating component of said phase currents detected by said first and second phase current detection parts.