Processing and Preparation of Advanced Stirling Convertors  for Extended Operation at NASA Glenn Research Center

Oriti, Salvatore M.; Cornell, Peggy A.

doi:10.2514/6.2008-5792

Cited by 5 publications

(1 citation statement)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A free-piston Stirling engine [1][2][3] connected with a linear motor [4][5][6] converting mechanical power into electrical power, which implements thermo-mechanical-electrical energy conversions, is called a free-piston Stirling power generating system. The combination of free-piston Stirling power generating system and linear motor formulates the thermo-mechanical-electrical system [7][8][9][10], which carries forward the advantages of both.…”

Section: Introductionmentioning

confidence: 99%

Research on Control Strategy of Free-Piston Stirling Power Generating System

et al. 2017

View full text Add to dashboard Cite

Abstract:As a clean and fuel adaptive alternative power plant, the Stirling power generating system has drawn attention of experts and scholars in the energy field. In practical application, the instability of free-piston Stirling power generating system caused by abrupt load change is an inevitable problem. Thus, methods to improve the output frequency response and stability of the free-piston Stirling power generating system are necessary. The model of free-piston Stirling power generating system is built by isothermal analysis firstly, and the initial control strategy based on given voltage system is put forward. To further improve the performance of power system, a current feedback decoupling control strategy is proposed, and the mathematical model is established. The influence of full decoupled quadrature-direct (d-q) axis currents is analyzed with respect to the output voltage adjusting time and fluctuation amplitude under the variations of piston displacement and output load. The simulation results show that the system performance is significantly improved, but the dynamic regulation lags caused by the decoupled current control still exist. To solve this problem and improve the performance of decoupled-state feedback current control that relies on parameter accuracy, internal model control based on sliding mode (IMC-SM) current decoupling control strategy is proposed, the system model is established, and then the performance of voltage ripple in generating mode is improved. Finally, the test bench is built, and the steady state and transient voltage control performances are tested. The feasibility and priority of the control strategy is verified by experiment and simulation results.

show abstract

Section: Introductionmentioning

confidence: 99%

Research on Control Strategy of Free-Piston Stirling Power Generating System

et al. 2017

View full text Add to dashboard Cite

show abstract

Extended Operation Testing of Stirling Convertors in Support of Stirling Radioisotope Power System Development

Lewandowski

Schreiber

Wilson

et al. 2008

6th International Energy Conversion Engineering Conference (IECEC)

View full text Add to dashboard Cite

100 We class Stirling convertors began extended operation testing at NASA Glenn Research Center (GRC) in 2003 with a pair of Technology Demonstration Convertors (TDCs) operating in air. Currently, the number of convertors on extended operation test has grown to 12, including both TDCs and Advanced Stirling Convertors (ASCs) operating both in air and in thermal vacuum. Additional convertors and an electrically heated radioisotope generator will be put on test in the near future. This testing has provided data to support life and reliability estimates and the quality improvements and design changes that have been made to the convertor.The convertors operated 24/7 at the nominal amplitude and power levels. Performance data were recorded on an hourly basis. Techniques to monitor the convertors for change in internal operation included gas analysis, vibration measurements and acoustic emission measurements. This data provided a baseline for future comparison. This paper summarizes the results of over 145,000 hours of TDC testing and 40,000 hours of ASC testing and discusses trends in the data. Data shows the importance of improved materials, hermetic sealing, and quality processes in maintaining convertor performance over long life.

show abstract