Reserve Power Unit Controller for Safe Energy Discharge

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Solution Overview

Problem

Current reserve power units (RPUs) do not effectively manage and discharge remaining energy, posing risks in hazardous environments and limiting their suitability for certain applications due to uncontrolled energy discharge.

Innovation Solution

A reserve power unit (RPU) that includes a controller to manage and discharge energy stored in capacitors or batteries, using a pulse-width modulated signal to control the discharge rate, ensuring safe operation and preventing overheating, and allowing for a controlled transition to a failsafe position in process control devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If remaining energy in the energy storage device is not discharged, then the RPU is simpler to operate, but it creates safety hazards in certain applications or environments

Engineering Contradiction:
ImprovesafetyVSAvoidenergy management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The RPU automatically monitors and discharges remaining energy in the energy storage device without requiring external intervention. The system self-manages the discharge process based on predefined safety criteria, eliminating the need for manual energy management while ensuring safety in hazardous environments.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The RPU incorporates monitoring mechanisms that detect the energy level in the storage device and provide feedback to the control system. When remaining energy exceeds safety thresholds, the system automatically initiates discharge operations, creating a closed-loop control system that maintains safety without continuous human oversight.

Inventive Principle:
Principle #23Feedback

2Reliability

If the energy storage device is fully discharged, then safety is improved in hazardous environments, but the time required for maintenance increases

Engineering Contradiction:
ImprovesafetyVSAvoidmaintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The RPU performs automatic discharge of remaining energy as a preliminary action before maintenance operations are required. By clearing residual energy in advance, the system eliminates the need for extended waiting periods during maintenance, as technicians can immediately service the device knowing it is in a safe, discharged state.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system rapidly discharges remaining energy through controlled discharge mechanisms, minimizing the time the device spends in a partially charged state. This allows the RPU to quickly transition to a safe discharged state, reducing overall maintenance time while maintaining safety requirements.

Inventive Principle:
Principle #21Skipping (Rushing through)

3Temperature

If pulse-width modulated signals are used to control discharge rate, then overheating is prevented, but the control system becomes more complex

Engineering Contradiction:
Improveoverheating preventionVSAvoidcontrol system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The RPU employs pulse-width modulated (PWM) signals to control the discharge rate of the energy storage device. By switching the discharge circuit on and off at controlled frequencies with variable duty cycles, the system regulates power dissipation and prevents overheating of discharge components while maintaining efficient energy discharge.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system replaces simple resistive discharge with electronically controlled PWM-based discharge. This substitution allows precise control of discharge current and power dissipation through digital control signals, preventing overheating while maintaining relatively simple hardware architecture through the use of standard PWM control circuits.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Ensures safe maintenance by fully discharging energy storage devices, preventing sparks in hazardous environments and ensuring process control devices reach a failsafe position, thereby reducing operational risks and enhancing safety.

Implementation Method 1

using a pulse-width modulated signal to control the discharge rate

Methodology Applied
Scientific EffectPulse-width modulation: Phase Modulation

Data Source

PatentEP3231058B1Self-discharging reserve power units and related methods
Publication Date: 2020.02.05 FISHER CONTROLS INT LLC
  • EP3231058B1 patent drawingFigure 1
  • EP3231058B1 patent drawingFigure 2-1
  • EP3231058B1 patent drawingFigure 2-2

AI summary

Self-discharging reserve power units and related methods are described. A self- discharging reserve power unit comprises an electrical energy storage component to provide power to a process control device. The electric energy storage component is coupled to an energy discharge component and a controller, which causes the discharge component to discharge energy from the electrical energy storage component following completion of an operation by the process control device.