Position detecting device and synchronous motor driving device using the same

• US 20070132423A1
• Filed: 12/11/2006
• Published: 06/14/2007
• Est. Priority Date: 12/12/2005
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Miyazaki, Hideki, Suwa, Tokihito, Sasaki, Masataka, Ajima, Toshiyuki, Furuyama, Bunji
• Application Number:
  US11/636,593
• Publication Number:
  US 20070132423A1
• Time in Patent Office: Days
• US Class Current: 318/719
• CPC Class Codes: G01D 5/2046 by a movable ferromagnetic element, e.g. a core
• CPC Class Codes: H02P 2209/07 Trapezoidal waveform
• CPC Class Codes: H02P 6/10 Arrangements for controlling torque ripple, e.g. providing reduced torque ripple
• CPC Class Codes: H02P 6/16 Circuit arrangements for detecting position

Abstract

A position detecting device which can increase accuracy in detecting the pole position of a motor used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed, and a synchronous motor driving device using the position detecting device. A position detector detects basic-wave component signals in sensor signals and executes position calculation. A correcting unit calculates signal information representing at least one of a gain, an offset and a phase by a phase detector from the basic-wave component signals detected by an error calculator, and makes correction based on the calculated signal information such that a position detection error is zero.

Claims

1. A position detecting device for detecting a motor pole position by using two or more sensor signals, said position detecting device comprising:

a position detector for detecting basic-wave component signals in said sensor signals and executing position calculation; and

correcting means for calculating signal information representing at least one of a gain, an offset and a phase from the detected basic-wave component signals, and making correction based on the calculated signal information such that a position detection error is zero.

2. The position detecting device according to claim 1, wherein said position detector extracts said sensor signals in a range between predetermined first and second determination values, thereby detecting said basic-wave component signals.

3. The position detecting device according to claim 1, wherein said position detector extracts sensor signals representing middle potentials of said sensor signals, thereby detecting said basic-wave component signals.

4. The position detecting device according to claim 1, wherein said sensor signal has a distorted waveform including a predetermined zone in which a sensor signal value is hardly changed.

5. The position detecting device according to claim 1, wherein said sensor signals are three-phase signals of U-, V- and W-phases, and

said position detector extracts a signal from a cross point between the U-phase signal and the W-phase signal to a cross point between the V-phase signal and the W-phase, a signal from a cross point between the V-phase signal and the W-phase signal to a cross point between the U-phase signal and the V-phase, and a signal from a cross point between the U-phase signal and the V-phase signal to a cross point between the U-phase signal and the W-phase, thereby detecting said basic-wave component signals.

6. The position detecting device according to claim 1, wherein said correcting means comprises:

an error calculator for calculating a position error amount from a position calculated value obtained by said position detector; and

a position corrector for correcting the position calculated value by using the position error amount calculated by said error calculator.

7. The position detecting device according to claim 1, wherein said correcting means includes a signal corrector for determining an error amount of said sensor signal from a difference between said signal information and a predetermined reference value, and for correcting the sensor signal such that the determined error amount is zero.

8. The position detecting device according to claim 1, further comprising a sensor unit for generating said sensor signal,

wherein said sensor unit includes a magnetic adjusting member for adjusting an amount of effective magnetic flux crossing a sensor.

9. The position detecting device according to claim 1, further comprising a sensor unit for generating said sensor signal,

wherein said sensor unit includes a magnetic shielding member oriented perpendicularly to a direction in which a sensor senses magnetic flux.

10. The position detecting device according to claim 1, further comprising a sensor unit for generating said sensor signal,

wherein said sensor unit includes a plurality of sensors attachable to a motor housing from the outside.

11. A position detecting device for detecting a motor pole position by using two or more sensor signals, said position detecting device comprising:

a position detector for detecting basic-wave component signals in said sensor signals and executing position calculation; and

correcting means for calculating signal information representing at least one of a gain, an offset and a phase from the detected basic-wave component signals, and making correction based on the calculated signal information such that a position detection error is zero,

wherein said position detector extracts said sensor signals in a range between predetermined first and second determination values, thereby detecting said basic-wave component signals.

12. A permanent-magnet synchronous motor driving device comprising:

a position detecting device for detecting a motor pole position by using two or more sensor signals; and

a motor controller for producing a PWM drive signal based on a position detected value detected by said position detecting device, and outputting the PWM drive signal to an inverter, thereby driving a permanent-magnet synchronous motor,

wherein said position detecting device comprises;

a position detector for detecting basic-wave component signals in said sensor signals and executing position calculation; and

correcting means for calculating signal information representing at least one of a gain, an offset and a phase from the detected basic-wave component signals, and making correction based on the calculated signal information such that a position detection error is zero.

13. The permanent-magnet synchronous motor driving device according to claim 12, wherein said motor controller includes a rotor position settling unit for driving said permanent-magnet synchronous motor through a predetermined electrical angle in a stepping manner under PWM control and settling a rotor stop position of said motor when the signal information is calculated by said correcting means, and

said correcting means of said position detecting device calculates, at a rotor position settled by said rotor position settling unit, a rotor position detection error from a difference between a value of the settled rotor position and the position detected value detected by said position detecting device,

said rotor position detection error being corrected.

14. The permanent-magnet synchronous motor driving device according to claim 12, wherein said motor controller receives a torque command, and

said permanent-magnet synchronous motor has a motive power load over a wide speed range from a stopped state to a state of large acceleration and deceleration.

15. The permanent-magnet synchronous motor driving device according to claim 12, wherein said motor controller receives a torque command from a vehicular control unit, and

said permanent-magnet synchronous motor has a vehicular motive power load over a wide speed range from a stopped state to a high-speed travel state.