Permanent Magnet Motor Control Device for Magnetic Pole Position Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional control devices for permanent magnet type rotating electrical machines face inaccuracies in magnetic pole position correction due to element variations and errors in dead time correction, leading to deteriorated accuracy in calculated magnetic pole position correction amounts.
Innovation Solution
The control device calculates actual d-axis and q-axis voltages from a midpoint potential detection unit and uses these values in a predetermined arithmetic expression to perform magnetic pole position origin correction, keeping d-axis and q-axis current command values near zero during dq vector control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic pole position correction is performed using d-axis voltage command value and q-axis voltage command value, then magnetic pole position correction can be implemented, but accuracy deteriorates due to element variations and dead time correction errors
Solution Approach 1:
The patent introduces an intermediary variable (actual voltage calculated from midpoint potential) to bridge the gap between command voltage and actual voltage. This intermediary measurement allows the system to compensate for dead time errors and element variations, thereby improving the accuracy of magnetic pole position correction without being directly affected by the inaccuracies in the voltage command values
Solution Approach 2:
The patent implements feedback by measuring the actual voltage through midpoint potential detection and using this measured value to calculate the magnetic pole position correction amount. This feedback mechanism allows the system to continuously adjust and improve correction accuracy by comparing actual system behavior with commanded behavior, thereby compensating for element variations and dead time errors
Data Source
AI summary
In order to reduce deviation of correction amount when calculating a magnetic pole position correction amount of a permanent magnet type rotating electrical machine, and perform magnetic pole position correction with high accuracy, in state where the permanent magnet type rotating electrical machine is rotated, a d-axis current command value and a q-axis current command value in dg vector control are kept substantially zero, an actual d-axis voltage and an actual q-axis voltage are calculated from a midpoint potential detected from a midpoint potential detection unit, a magnetic pole position correction amount is calculated based on a predetermined arithmetic expression from the actual d-axis voltage and the actual q-axis voltage, and magnetic pole position origin correction is performed based on the magnetic pole position correction amount.