Active Rectifier Control for Drilling Power Generation

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Solution Overview

Problem

Power generation systems in drilling rigs face issues such as poor power factor, low efficiency, and high current harmonic distortion, necessitating a solution for a regulated DC supply with minimum input current harmonic distortion and unity power factor, along with a wide input voltage range and fast dynamic control.

Innovation Solution

A turbine-driven alternator system with active electronic rectification, including a magnetic coupling, gear box, and active rectifier control, which converts AC to DC and employs a capacitor bank to manage energy efficiently, eliminating the need for additional protection circuitry and allowing for sensorless operation by estimating rotor flux and speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional power generation system is used in drilling tools, then the system can generate power, but it suffers from poor power factor, low efficiency, and high current harmonic distortion

Engineering Contradiction:

Improvepower generation efficiencyVSAvoidcurrent harmonic distortion

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent replaces conventional mechanical rectification systems with an active electronic rectification system that uses power electronics to convert AC to DC. This electronic substitution enables precise control of the rectification process, achieving unity power factor and minimizing harmonic distortion while maintaining high efficiency. The active rectifier uses switching devices and control circuits to regulate current flow and eliminate the harmful effects of conventional passive rectification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent dynamically adjusts electrical parameters including voltage, current, and frequency to optimize power conversion efficiency. The active rectification system continuously monitors and modifies these parameters to maintain unity power factor across varying operating conditions, thereby eliminating harmonic distortion and maximizing energy efficiency in the power generation system.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If additional protection circuitry is added to the power generation system, then system reliability improves, but device complexity increases

Engineering Contradiction:

Improvesystem reliabilityVSAvoidprotection circuitry complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The active rectification system incorporates built-in protective functions that automatically detect and respond to fault conditions without requiring external protection circuits. The control system continuously monitors system parameters and implements protective actions such as shutting down or adjusting operation when anomalies are detected, thereby achieving high reliability through self-protection mechanisms that add minimal complexity.

Inventive Principle:

Principle #25Self-service

3Device complexity

If sensorless operation is implemented by estimating rotor flux and speed, then device complexity is reduced, but measurement precision may be affected

Engineering Contradiction:

Improvesensor requirementsVSAvoidrotor flux and speed estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent uses electrical parameters such as current and voltage measurements as intermediaries to indirectly estimate rotor flux and speed without requiring physical sensors. The control system processes these electrical signals through mathematical models and algorithms to derive accurate rotor position and speed information, achieving sensorless operation with sufficient precision for effective control while significantly reducing device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system provides a high-efficiency, regulated DC supply with unity power factor, minimizing harmonic distortion and enabling fast dynamic control, thus enhancing the operational reliability and efficiency of downhole tools in drilling rigs.

Implementation Method 1

an alternator driven by the turbine

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

one or more converters that convert AC voltage output from the alternator to DC voltage

Methodology Applied

Scientific EffectRectification:

Implementation Method 3

employs a capacitor bank to manage energy efficiently

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10972028B2Dynamic generator voltage control for high power drilling and logging-while-drilling

Publication Date: 2021.04.06 HALLIBURTON ENERGY SERVICES INC

AI summary

A power generation system for a drilling tool includes a turbine, an alternator, a converter and a first active rectifier control (ARC). The turbine is adapted to be driven by a fluid flow in a well. The alternator is coupled to the turbine and generates an alternative current (AC). The converter converts the AC to direct current (DC) and carries out active rectification. The first active rectifier control (ARC) controls the active rectification of the converter.