Parallel Motor Drive PI Control for Integrator Saturation Balance
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Solution Overview
Problem
Parallel motor drive systems face issues with integrator saturation due to single event upsets and local component and sensor tolerances, leading to unstable system behavior and current imbalances.
Innovation Solution
A proportional integrator is designed to receive input commands and local measured signals, with a correction factor added to balance the integral term based on total current reference commands from all connected motor drives, incorporating a global input signal to prevent saturation and ensure seamless operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If multiple motor drives share a common power supply to reduce system size and weight, then component count and complexity are reduced, but integrator saturation and current imbalance occur due to single event upsets and component tolerances
Solution Approach 1:
The patent implements a feedback mechanism where the proportional integrator continuously monitors the current reference commands from all parallel motor drives and dynamically adjusts the integral term with a correction factor. This feedback loop detects integrator saturation conditions and corrects them in real-time, maintaining current balance and system stability while allowing multiple drives to share a common power supply
Solution Approach 2:
The patent modifies the integral term parameter of the proportional integrator by adding a correction factor that depends on the sum of current reference commands from all parallel drives. This parameter change allows the integrator to adapt its behavior under parallel operation conditions, preventing saturation caused by component tolerances and single event upsets while maintaining the benefits of shared power supply
2Reliability
If a correction factor is added to the proportional integrator to balance current outputs, then integrator saturation is mitigated, but control structure complexity increases
Solution Approach 1:
The patent applies local quality by implementing the correction factor specifically within the proportional integrator's integral term, rather than redesigning the entire control system. The correction factor is calculated locally based on the sum of current reference commands from parallel drives and is applied only where needed (in the integral term), maintaining simplicity in other parts of the control structure while achieving saturation mitigation
Data Source
AI summary
A proportional integrator for control of a motor drive arranged to be connected in parallel with one or more other motor drives to drive a common load. The proportional integrator includes means to receive an input command signal and to compare with a local measured signal from the motor drive and to output a local control signal for that motor drive. Also includes are a global input signal indicative of the behaviour of the one or more other motor drives, the global input signal being incorporated into the proportional integral function with the input command signal and the local measured signal to provide the local control signal.