Motor control device

Abstract

Disclosed is a motor control device, which can detect the rotor position of a synchronous motor with constant precision and at a low processing load. The motor control device detects the rotor position (thelta m) by determining directly said rotor position (thelta m) using a rotor position formula (thelta m=thelta i-beta-90 DEG ) which includes, as variables: the phase current electrical angle (thelta i) from among the phase current peak value (Ip) and a phase current electrical angle (thelta i), which are detected by a phase current peak value and electrical angle detection unit (19), and the induced voltage peak value (Ep) and an induced voltage electrical angle (thelta e), which are detected by an induced voltage peak value and electrical angle detection unit (20); and a current phase (beta) which can be selected from a pre-prepared data table using [a phase current peak value (Ip)] and [an induced voltage electrical angle (thelta e) - a phase current electrical angle (thelta i)] as parameters.

Description

technical field [0001] The present invention relates to a motor control device that detects a rotor rotational position (hereinafter referred to as a rotor position) of a synchronous motor in a sensorless manner. Background technique [0002] In the sine-wave driving method (180-degree energization method) known as a driving method of a synchronous motor such as a three-phase direct current (DC) brushless motor, the rotor position is detected sensorlessly in order to energize the stator coil appropriately. [0003] Regarding rotor position detection, Patent Document 1 discloses a method of obtaining a first phase difference between the motor current and the actual rotational position and at the same time obtaining a second phase difference between the motor current and the virtual rotational position, and using the first phase difference and the The difference between the second phase difference is used to estimate the phase error between the actual rotation position and the...

AI Technical Summary

Problems solved by technology

[0005] However, with the motor position detection methods disclosed in Patent Documents 1 and 2, since the virtual rotor position is basically corrected based on predetermined conditions to detect the desired rotor position, the rotor position detection accuracy varies depending on the correction accuracy.

In addition, since the process from obtaining the virtual rotor position to correcting the rotor position has to be repeated at high speed, it is necessary to have a high-capacity data processing device corresponding to a high processing load.

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