Rotor Pole Position Correction for High-Speed Motor Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing synchronous motor control devices struggle to correct magnetic pole position errors in rotating electric machines, especially at high rotation speeds due to counter-electromotive forces that prevent d-axis current from being reduced to zero.
Innovation Solution
A control device that adjusts voltages in the d-axis and q-axis directions, acquires current data to determine a correction amount for the magnetic pole position, and applies this correction using equations based on angular velocity, inductance, and current data, allowing for accurate pole position correction even at high speeds without requiring zero q-axis current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the d-axis current command and q-axis current command are set to zero to correct magnetic pole position error, then the magnetic pole position correction can be performed, but at high rotation speeds the counter-electromotive force becomes large and prevents the d-axis current from being reduced to zero, making correction impossible
Solution Approach 1:
The invention changes the control parameters from setting current commands to zero to setting voltage commands to zero. This parameter change allows the correction method to work at high speeds where current-based methods fail, as the voltage control can overcome the counter-electromotive force issue and enable the d-axis current to actually reach zero even when the machine is rotating at high speed
Solution Approach 2:
The invention performs preliminary voltage control to bring the d-axis voltage to zero before attempting to measure the q-axis current for correction calculation. This preliminary action ensures that the system is in the correct state for accurate magnetic pole position correction, regardless of the initial rotation speed or current conditions
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
Enables accurate correction of magnetic pole position errors in rotating electric machines at high speeds, ensuring stable operation and improved precision in vehicle systems by determining correction amounts based on stable rotor conditions and electrical characteristics.
Implementation Method 1
a magnetic pole position detector for detecting a magnetic pole position of the rotor is attached
Implementation Method 2
a stator for generating a magnetic field using a winding
Implementation Method 3
a rotating electric machine driven by an electric power supplied from an inverter
Data Source
AI summary
A control device executes: controlling a voltage in a d-axis direction and a voltage in a q-axis direction applied to a rotating electric machine driven by an electric power supplied from an inverter, to which a magnetic pole position detector for detecting a magnetic pole position of the rotor is attached, and which includes a stator for generating a magnetic field using a winding; acquiring q-axis current data indicating a component in the q-axis direction of a current flowing through the rotating electric machine when a component in the d-axis direction of the voltage applied to the rotating electric machine is equal to or less than a predetermined voltage; and determining, based on the q-axis current data, a correction amount of the magnetic pole position satisfying a condition that a current indicated by the q-axis current data is equal to or less than a predetermined current and correcting the magnetic pole position based on the correction amount.