Motor drive apparatus
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Solution Overview
Problem
The existing motor drive apparatuses require a heavy workload for adjusting control parameters to prevent the windup phenomenon and maintain stable control, especially due to the complex non-linear characteristics of servo systems and many control parameters needing adjustment.
Innovation Solution
A motor drive apparatus that includes a current controller, a voltage amplitude calculating unit, a speed controller, a flux weakening controller, and a speed droop controller, which convert phase currents into d-axis and q-axis currents, determine voltage commands, and control rotational speed and voltage amplitude to prevent windup and stabilize motor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control method from Patent Literature 1 is applied to prevent windup phenomenon, then the stability of control is improved, but the workload for adjusting control parameters increases significantly
Solution Approach 1:
The control device automatically determines whether voltage saturation is occurring and adjusts the speed command value accordingly, without requiring manual intervention or complex parameter tuning by the operator. The system self-regulates based on detected saturation conditions
Solution Approach 2:
The control device detects the saturation state of the power converter output and uses this feedback information to automatically adjust the speed command value, creating a closed-loop system that responds to actual operating conditions
2Manufacturing precision
If multiple control parameters are adjusted to achieve stable control, then the control precision is improved, but the time required for adjustment increases
Solution Approach 1:
The control device is pre-configured with the capability to detect voltage saturation and automatically adjust speed command values, so that when saturation occurs, the system can immediately respond without requiring time-consuming manual parameter adjustments
Solution Approach 2:
The system automatically performs the adjustment function that would otherwise require manual intervention, eliminating the time loss associated with operator-adjusted parameters
Data Source
AI summary
A motor drive apparatus includes: a dq-axis current controller converting phase current flowing through a synchronous motor into d-axis current and q-axis current, and controlling the phase current by determining a voltage command based on the d-axis current and a d-axis current command as well as the q-axis current and a q-axis current command; a voltage amplitude calculating unit obtaining voltage amplitude; a speed controller controlling rotational speed of the motor by determining the q-axis current command based on a speed command, the rotational speed, and a speed droop amount that reduces the speed command; a flux weakening controller performing flux control to limit amplitude of voltage output to the motor by determining the d-axis current command based on the voltage amplitude and a first voltage limit value; and a speed droop controller controlling the speed droop amount based on the voltage amplitude and a second voltage limit value.