Parallel Motor Drive Integrator Control for Single Event Upsets
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Solution Overview
Problem
Existing parallel motor drive systems face instability due to single event upsets, which can cause sudden integrator saturation and destabilize the system, particularly when multiple drives are connected in parallel.
Innovation Solution
A proportional integrator is incorporated into the current and speed control loops, using a global voltage reference based on local references from all connected motor drives to initialize and balance the integrators, mitigating the effects of single event upsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple motor drives are connected in parallel to reduce system size and weight, then the quantity of components and system weight are reduced, but the system becomes vulnerable to single event upsets that can cause integrator saturation and destabilize the system
Solution Approach 1:
The patent implements a feedback mechanism where the global voltage reference is continuously updated based on the sum of local voltage references from all parallel-connected motor drives. This feedback loop ensures that each drive's integrator state is synchronized with the collective system state, preventing integrator saturation and maintaining system stability even when individual drives experience single event upsets.
Solution Approach 2:
The patent creates an equipotential condition among parallel motor drives by initializing each drive's integrator using a common global voltage reference. This ensures all drives start from the same electrical potential and operating point, preventing current transients and instability that would otherwise occur when drives have mismatched integrator states.
2Reliability
If a global voltage reference based on local references from all drives is used to initialize integrators, then system stability is maintained and current balance is achieved, but the control architecture complexity increases
Solution Approach 1:
The patent segments the control architecture into independent modular units, where each motor drive has its own local controller that computes its local voltage reference independently. The global voltage reference is then formed by summing these independent local references, allowing each module to operate autonomously while maintaining overall system coherence through the simple additive relationship.
3Reliability
If integrators are initialized after every computational step to prevent saturation, then single event upset effects are mitigated, but the computational overhead and processing time increase
Solution Approach 1:
The patent performs preliminary initialization of integrators by setting them to the global voltage reference at the beginning of each control cycle or computational step. This preliminary action prevents integrator saturation from occurring during the computational step, eliminating the need for corrective reset operations and reducing overall computational overhead.
Data Source
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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 comprising 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, further comprising 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.