Analysis and modeling of novel brushless exciter based on hybrid excitation topology
The exciter is a key component of the synchronous generator system with self-excited initiation. Based on the topology of hybrid excitation, this paper proposes a novel brushless exciter, which is suitable for an isolated power system. The parameters of the exciter are calculated by the numerical method based on finite element model, and the state space model is established. The experimental researches are carried out on a 3 kW prototype.
Research on self-excited initiation of a Medium-voltage DC (MVDC) multiphase synchronous generator-rectifier system
This paper has described the excitation system of a Medium-voltage DC (MVDC) multiphase synchronous generator-rectifier system and calculated the minimum frequency of the pilot-exciter needed for self-excited initiation. On this basis, a double closed-loop V/F control method is proposed according to the classical PI control algorithm for self-excited initiation. With the method, a prototype is constructed for test. The results show that both the self-excitation initiating and the speed-rising processes of the generator set have changed synchronously thus to reduce the time needed for MVDC multiphase synchronous generator-rectifier system to start and finish establishing the nominal DC voltage.
Air scrubbing techniques for ammonia and odor reduction at livestock operations : review of on-farm research in the Netherlands
Acid scrubbers and biotrickling filters have been developed for ammonia (NH3) removal at pig and poultry houses 
in The Netherlands over the last 20 years to prevent acidification and eutrophication of soils. Because of growing 
suburbanization, odor removal is increasingly considered important as well. In this review, we report the results of the on-farm 
research on full-scale operated scrubbers for treatment of exhaust air from animal houses with regard to NH3 and odor 
removal in The Netherlands. The NH3 removal of acid scrubbers ranged from 40% to 100% with an overall average of 96%. 
The NH3 removal of biotrickling filters ranged from -8% to +100% with an overall average of 70%. Minimum empty bed air 
residence times (EBRTs) were 0.4 to 1.1 s. For acid scrubbers, process control with pH measurement and automatic water 
discharge is sufficient to guarantee sufficient NH3 removal. For biotrickling filters, however, improvement of process control 
is necessary to guarantee sufficient NH3 removal. The odor removal of acid scrubbers ranged from 3% to 51% with an overall 
average of 27%. The odor removal of biotrickling filters ranged from -29% to +87% with an overall average of 51%. 
Minimum EBRTs were 0.5 to 2.3 s. Further research is necessary to explain this variation and to improve the odor removal 
efficiency of both acid scrubbers and biotrickling filters.