Position detecting device and synchronous motor driving device using the same

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.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a position detecting device for detecting a motor pole position and a synchronous motor driving device using the position detecting device. More particularly, the present invention relates to a position detecting device and a synchronous motor driving device using the same, which are suitably used to perform acceleration and deceleration over the range from a zero speed (stopped state) to a high rotation speed. [0003] 2. Description of the Related Art [0004] As one of devices for driving a synchronous motor (hereinafter referred to simply as a “motor”), there is known a type of driving the motor by using a position detecting device which detects a rotor pole position. Here, the term “position detecting device” means a device, such as a resolver or an absolute rotary encoder, which can not only detect a motor rotational angle during rotation, but also determine an absolute position in...

AI Technical Summary

Benefits of technology

[0007] As disclosed in Japanese Patent No. 3315847, in the field of the synchronous motor, there is known a position detecting method using an inexpensive Hall device as a position sensor which can not only detect a motor rotational position during rotation, but also determine an absolute position in the stopped state. Further, the technique for making correction based on the maximum and minimum values of the sensor signal is proposed to eliminate the influence of temperature change of the Hall device itself.

[0011] An object of the present invention is to provide 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.

[0013] With those features, it is possible to increase the accuracy in detecting the pole position of a motor which is used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed.

[0024] With those features, it is possible to increase the accuracy in detecting the pole position of a motor which is used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed.

[0026] With those features, it is possible to increase the accuracy in detecting the pole position of the motor which is used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed.

[0030] According to the present invention, higher accuracy can be obtained in detecting the pole position of the motor which is used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed.

Problems solved by technology

For that reason, detection resolution is deteriorated and the accuracy in position detection becomes eventually insufficient, thus leading to a problem that specifications required for the synchronous motor cannot be satisfied.

Another problem is that, because a deviation of the mount position is not corrected, convenience in fabrication and maintenance is not satisfactory.

However, because the position error between the motor rotor (magnet position) and the position sensor is corrected by executing the pole-position estimating calculation based on the motor applied voltage, the motor current, and the motor constants, complicated pole-position estimating calculation is required.

Another problem is that high accuracy of the position sensor cannot be achieved because calculation errors caused by variations in the motor constants due to mass-production and variations in accuracy of current detection impose a limitation in correction of the position detected value.

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