DC Power Plant Start-Up Using a Capacitor-Assisted Engine Drive
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Solution Overview
Problem
Existing systems for generating direct current (DC) power face inefficiencies due to the need for conversion from alternating current (AC) power, particularly in centralized power transmission, and lack effective means for starting engines like Stirling engines efficiently while managing power flow and emissions.
Innovation Solution
A modular power system that includes a backplane, microprocessors, half-bridge circuits, power conditioning elements, and sensors to control rotating power generators, enabling efficient DC power production, starting engines with a small power supply and capacitor bank, and managing power flow, emissions, and system control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If AC power is converted to DC power through traditional centralized power transmission, then power can be transmitted long distances, but conversion inefficiencies are introduced
Solution Approach 1:
The patent extracts the DC power generation capability directly at the source by using a Stirling engine coupled with a DC generator, eliminating the need for AC-to-DC conversion in centralized power transmission. This direct DC generation approach removes the conversion inefficiency while preserving long-distance transmission capability through DC power lines.
Solution Approach 2:
The patent replaces the traditional AC generation and conversion mechanical system with a direct DC generation system using a Stirling engine coupled to a DC generator. This substitution eliminates the AC-to-DC conversion step and its associated losses, achieving more efficient power transmission.
2Reliability
If a Stirling engine is started with a large power supply, then the engine can be started reliably, but the start-up power supply size and cost increase
Solution Approach 1:
The patent applies preliminary action by using a capacitor bank to store energy before engine start-up. The capacitor bank is charged in advance and then discharged to provide the high starting torque needed for the Stirling engine, eliminating the need for a continuously large power supply while ensuring reliable starting.
Solution Approach 2:
The patent uses periodic action by employing a motor controller that delivers pulsed or periodic starting current to the motor coupled with the Stirling engine. This periodic current delivery provides the necessary starting torque in controlled bursts, reducing the overall power supply requirements while maintaining starting reliability.
3Ease of operation
If start-up circuits remain connected during engine operation, then the circuits remain powered, but unnecessary power consumption occurs
Solution Approach 1:
The patent uses preliminary action by providing power to start-up circuits only when needed - specifically during engine start-up and shutdown phases. A controller monitors engine status and activates the start-up circuits only during these critical periods, preventing unnecessary power consumption during normal operation while ensuring circuits are powered when required.
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 enhances efficiency in DC power generation, reduces emissions, and provides reliable power management for loads, including disabling output during abnormal conditions and controlling engine velocity, thereby improving overall power plant performance.
Implementation Method 1
A motor controller is coupled to the motor and supplies starting current from a capacitor bank
Implementation Method 2
A motor is coupled to the Stirling engine
Implementation Method 3
A Stirling engine is to be started and is coupled to a generator
Implementation Method 4
A generator is coupled to the Stirling engine and produces direct current (DC) power
Data Source
AI summary
A DC power plant generating DC power from a variety of engines including a Stirling cycle engine. The DC power plant includes a relatively small start-up power source that is discontinued after the engine is running. A method for producing DC power for a load including starting up an engine using power supplied by a relatively small power supply supplemented by a capacitor bank, providing output from the engine to a generator, producing alternating current (AC) power by the generator, converting the AC power to direct current (DC) power, disabling output of the DC power during a first set of pre-selected conditions, limiting a rate of change of current of the DC power during a second set of pre-selected conditions, reducing conducted and radiated emissions of the DC power, disconnecting the DC power from the load under a third set of pre-selected conditions, and providing the DC power to the load.