Control device and control method of synchronous motor

Abstract

The invention provides a control device and a control method of a synchronous motor. The device comprises a d-axis current calculation portion (12) which calculates d-axis current calculation value for controlling weak field magnet based on a maximum line-to-line voltage (Vmax) calculated by a maximum line-to-line voltage calculation portion and an electric angle speed (Omega e) of a PM motor (1), and a weak field magnet control switching portion (13) which outputs any one of the d-axis current calculation value for controlling weak field magnet and a d-axis current setting value for controlling maximum torque as a d-axis current instruction value (Id*)according to the maximum line-to-line voltage (Vmax) and the electric angle speed (Omega e) of a PM motor (1). The d-axis current calculation value is calculated by the d-axis current calculation portion (12) based on the maximum line-to-line voltage (Vmax) and the electric angle speed (Omega e) of the PM motor (1) as counter electromotive force factors (Ke) of the motor parameters of the PM motor (1).

Description

technical field [0001] The present invention relates to a control device and a control method of a synchronous motor, in particular to a control device and a control method of a synchronous motor which can stably switch to weak-field magnetic control. Background technique [0002] When the permanent magnet synchronous motor is controlled at a speed equal to or higher than the base rotational speed, switching is performed for field-weakening control in which the magnetic flux generated by the permanent magnets is controlled to be weak by the d-axis current. Judgment on the switching of field-weakening control is based on the comparison between the base speed and the motor speed. However, in the case of devices with large DC voltage fluctuations, sometimes the inverter output voltage is saturated at speeds below the base speed and cannot be adjusted. Take control. [0003] Therefore, the applicant of the present invention disclosed a technology capable of stably switching bet...

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Problems solved by technology

[0005] However, in Patent Document 1, the input specification of the main circuit part is a specific motor whose input specification is a battery-based DC power supply. The problem that I cannot cope with any motor

That is, in Patent Document 1, a relatively stable battery is used as a DC power supply, but in a DC power supply based on 3-phase AC + diode rectification, switching for field-weakening control becomes unstable due to fluctuations in DC voltage

In addition, in Patent Document 1, since the d-axis current calculation is performed using table data for a specific motor, it cannot be used for any motor.

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