Virtual Damper Algorithm for Permanent Magnet Motor Transient Stability

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Solution Overview

Problem

Controlling and stabilizing permanent magnet motors used in electric submersible pumps for oil and gas applications is challenging due to instability and inefficiency, especially during transient events, as they lack robust control mechanisms compared to induction motors.

Innovation Solution

Implementing a virtual damper system controlled by a controller that adjusts torque and speed of the permanent magnet motor through a virtual damping algorithm, simulating the effect of a damper cage without physical components, to stabilize operation and mitigate torque pulsations and voltage spikes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a permanent magnet motor is used instead of an induction motor, then power density and efficiency are improved, but control stability and ease of operation deteriorate during transient events

Engineering Contradiction:

Improvepower densityVSAvoidcontrol stability

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

A virtual damper algorithm acts as an intermediary control mechanism that simulates the effect of a physical damper cage. The algorithm processes motor current and voltage signals to generate corrective torque commands that stabilize the motor during transient events, bridging the control gap between the permanent magnet motor's high performance and its natural instability during transients.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/physical damper cage structure with a software-based virtual damper algorithm. Instead of using physical components to provide damping, the system uses computational processing of electrical signals to achieve the same stabilizing effect, eliminating the need for additional hardware while maintaining control stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a virtual damper algorithm is implemented, then control stability during transient events is improved, but device complexity increases

Engineering Contradiction:

Improvecontrol stabilityVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The virtual damper algorithm is self-regulating and automatically adjusts its damping action based on real-time motor operating conditions. The system monitors its own state through current and voltage sensors and autonomously generates corrective commands without requiring external intervention or complex tuning, reducing the operational burden despite the added algorithmic complexity.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The algorithm dynamically changes control parameters based on operating conditions, specifically adjusting damping torque commands in response to detected transient events. By modifying control parameters adaptively rather than using fixed complex control structures, the system achieves improved stability with relatively simple implementation.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If physical damper cage components are added to the motor, then stability during transient events is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvemotor stabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent substitutes mechanical/physical damper cage components with a software-based virtual damper algorithm. This replacement eliminates the need for additional physical parts, simplifying manufacturing while achieving the same stability improvement through computational control of the existing motor windings and power electronics.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The virtual damper algorithm creates a computational copy or simulation of the damper cage's stabilizing effect. Rather than building the physical structure, the system replicates its functional behavior through software processing of electrical signals, achieving identical stability benefits without manufacturing complexity.

Inventive Principle:

Principle #26Copying

Data Source

PatentUS10256762B2Systems and methods for active damping of a motor

Publication Date: 2019.04.09 GE INFRASTRUCTURE TECH LLC

AI summary

A method includes controlling a first power output to an electric machine during a transient event. Controlling the first power output includes measuring values of the first power output provided to the electric machine during the transient event, receiving an estimated speed input of the electric machine, determining adjustment commands to compensate the first power output for the transient event of the electric machine, generating switch commands for gate drives of a variable frequency drive (VFD) based at least in part on the adjustment commands, and modifying the first power output during the transient event based on the switch commands.