In this paper, an integral criterion is developed for the overall analysis and appraisal of the performance, reliability and economy of a computer-based control system. A concept of performability is discussed, and the economic optimality is based on the overall benefits from the manufacturer to the user. A case study for a hydroturbine governing system is given. A comparison between different system configurations shows that it is helpful and beneficial to select a system possessing high indices and excellent quality 相似文献
The details are given of the hardware and software and the field test results for a duplicate microprocessor-based governor (DμPG). An evaluation of the financial benefits with examples from the 11 DμPGs operating at seven different hydro-power plants in China is given. A proposal is presented for a new DμPG with a control strategy based on intelligent self-improvement 相似文献
A highly reliable fault tolerant microprocessor-based governor with high performance is being developed. In this system, techniques such as redundancy, fault detection, fault location, fault isolation, and self-recovery have been applied successfully to achieve high reliability. The hardware architecture of this system and its fault tolerance aspects are described. The software structure and the redundancy architecture are presented. The fault detection, the fault location, and the fault isolation techniques applied to this system are studied. The self-recovery and reconfiguration of the system and the switch-over control based on the fault detection results are discussed 相似文献
The presence of defects/vacancies in nanomaterials influences the electronic structure of materials, and thus, it is necessary to study the correlation between the optoelectronic properties of a nanomaterial and its defects/vacancies. Herein, we report a facile solvothermal route to synthesize three-dimensional (3D) SnS nanostructures formed by {131} faceted nanosheet assembly. The 3D SnS nanostructures were calcined at temperatures of 350, 400, and 450 °C and used as counter electrodes, before their photocurrent properties were investigated. First principle computation revealed the photocurrent properties depend on the defect/vacancy concentration within the samples. It is very interesting that characterization with positron annihilation spectrometry confirmed that the density of defects/vacancies increased with the calcination temperature, and a maximum photocurrent was realized after treatment at 400 °C. Further, the defect/vacancy density decreased when the calcination temperature reached 450 °C as the higher calcination temperature enlarged the mesopores and densified the pore walls, which led to a lower photocurrent value at 450 °C than at 400 °C.
