Parallel Motor Drive Integrator Control for Current Balance

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Solution Overview

Problem

Existing parallel motor drive systems face issues with integrator saturation due to single event upsets and gradual saturation caused by local component and sensor tolerances, leading to destabilization and current imbalances.

Innovation Solution

A control scheme that modifies proportional integrators in each motor drive by incorporating a global voltage reference and feedback signal to prevent saturation, using appropriate gains to balance the integrators across drives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If multiple motor drives share a common power supply to reduce system size and weight, then the number of components and system weight are reduced, but integrator saturation and current imbalance occur due to component tolerances

Engineering Contradiction:

Improvesystem weightVSAvoidintegrator saturation

Core Design Contradiction:

Weight of stationary objectVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where each motor drive's proportional integrator receives feedback about the global voltage reference and subtracts its own local voltage reference contribution. This feedback loop prevents integrator saturation by continuously adjusting the integrator output based on the actual system state and the behavior of other parallel drives, ensuring current balance despite component tolerances

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent modifies the proportional integrator parameters by introducing a feedback gain and adjusting the integrator input signal. The integrator receives a modified signal that incorporates feedback about the global voltage reference, effectively changing the integrator's operating parameters to prevent saturation while maintaining current balance across parallel drives

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a single motor drive is used to power multiple loads to reduce complexity, then device complexity is reduced, but the drive cannot handle simultaneous operation of all loads

Engineering Contradiction:

Improvedevice complexityVSAvoidload handling capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent makes each motor drive universal by enabling it to operate in multiple modes: it can function as a standalone drive for individual loads or as part of a parallel configuration for larger loads. The control architecture allows each drive to adapt its operating mode based on system requirements, providing both reduced complexity and enhanced versatility

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4329185B1Control structures for parallel motor drive control architectures

Publication Date: 2026.01.21 HAMILTON SUNDSTRAND CORP

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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.