Synchronous Motor Pole Detection With Rotor Oscillation Damping
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Solution Overview
Problem
Synchronous motors experience significant oscillation during direct-current excitation, which can limit their rotation range and prolong the time required for magnetic pole position detection, particularly in applications like drive shafts for machine tools.
Innovation Solution
A control device that generates a deceleration torque command based on rotor angular acceleration and velocity to reduce rotor oscillation amplitude during direct-current excitation, using a magnetic pole position detection unit to acquire the rotor's angular position when specific detection conditions are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct-current excitation is applied to detect initial magnetic pole position, then magnetic pole position detection can be performed, but rotor oscillation occurs which limits rotation range and prolongs detection time
Solution Approach 1:
The control device applies deceleration torque during the oscillation period to actively dampen rotor oscillation. By detecting angular acceleration and angular velocity, the system determines when to apply deceleration torque, thereby reducing oscillation amplitude and shortening the time required for magnetic pole position detection to meet the predetermined time period.
2Measurement precision
If direct-current excitation is applied to detect initial magnetic pole position, then magnetic pole position detection can be performed, but rotor oscillation occurs which limits rotation range
Solution Approach 1:
The control device applies deceleration torque during the oscillation period to actively dampen rotor oscillation. By detecting angular acceleration and angular velocity, the system determines when to apply deceleration torque, thereby reducing oscillation amplitude and shortening the time required for magnetic pole position detection to meet the predetermined time period.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces rotor oscillation amplitude and shortens the time required for magnetic pole position detection, enhancing the efficiency of synchronous motor control.
Implementation Method 1
A synchronous motor passes current in a suitable phase according to a magnetic pole position of a rotor and generates desired torque
Implementation Method 2
a direct-current excitation command generation unit configured to generate a command for passing direct current in a fixed current phase through the synchronous motor and control magnitude of the direct current in such a way as to apply deceleration torque to the rotor, based on at least either of angular acceleration and angular velocity of the rotor
Data Source
AI summary
Provided is a control device for a synchronous motor, the control device including a DC excitation command generation unit which generates a command for sending a DC current with a fixed current phase to a synchronous motor, and controls the magnitude of the DC current so as to apply deceleration torque to a rotor of the synchronous motor on the basis of at least one among the angular acceleration and the angular velocity of the rotor; and a magnetic pole position acquisition unit that acquires, as information indicating the magnetic pole position, the angular position of the rotor based on the output signal when a predetermined detection end condition is satisfied.