Subsea Motor Drive Segmentation for Harsh Environment Control
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Solution Overview
Problem
Conventional motor drives for subsea oil and gas applications face reliability issues due to harsh environmental conditions, making maintenance and replacement costly and time-consuming, especially when deployed thousands of feet below the surface.
Innovation Solution
A system comprising an above-surface control unit and a subsea motor drive unit, where the subsea unit includes semiconductor switches and a communications circuit to receive control signals from the above-surface unit via a high-speed link, such as a fiber optic cable, allowing for efficient control and monitoring of subsea motors while keeping vulnerable control circuitry above-surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If motor drive equipment is deployed subsea for oil and gas applications, then operational capability in harsh environments is achieved, but reliability deteriorates due to intense pressures and temperatures
Solution Approach 1:
The motor drive system is divided into separate functional modules: power conversion equipment on the surface and motor control equipment subsea. This segmentation allows the sensitive control components to be protected from harsh environmental conditions while maintaining subsea operational capability through remote control via communications cable.
Solution Approach 2:
A communications cable serves as an intermediary between surface-based power conversion equipment and subsea motor control equipment. This intermediary enables control signals and power to be transmitted to the subsea environment without exposing sensitive control circuitry to harsh pressures and temperatures.
2Ease of operation
If motor drive equipment is deployed subsea, then remote operational capability is achieved, but maintenance and replacement become time-consuming and expensive
Solution Approach 1:
By separating control functions into distinct subsea and surface components, the system enables remote operation while facilitating easier maintenance. The subsea motor control equipment can be maintained or replaced independently without requiring complete system shutdown or complex subsea intervention.
Solution Approach 2:
The communications cable acts as a maintained connection that allows continuous monitoring and control during maintenance operations, enabling diagnostics and parameter adjustments without physical access to subsea equipment.
3Device complexity
If control circuitry is placed subsea with motor drives, then integrated control is achieved, but vulnerability to harsh conditions increases
Solution Approach 1:
The control system is segmented into surface-based power conversion equipment and subsea motor control equipment. This separation protects sensitive control circuitry from harsh subsea conditions while maintaining integrated control functionality through the communications cable connection.
Solution Approach 2:
Sensitive control circuitry is extracted from the subsea environment and placed on the surface, removing the vulnerability of electronic components to intense pressures and temperatures while retaining the ability to control subsea motors remotely.
Data Source
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AI summary
A system includes an above-surface control unit and a subsea motor drive unit. The above-surface control unit includes a variable speed motor control circuit configured to generate at least one switch control signal and a first communications circuit configured to transmit the at least one switch control signal over a communications medium. The subsea motor drive unit includes a driver circuit configured to be coupled to an electric motor and comprising at least one semiconductor switch and a second communications circuit coupled to the first communications circuit via the communications medium and configured to recover the transmitted at least one switch control signal and to apply the recovered at least one switch control signal to the driver circuit.