DC/DC-converters in parallel operation with digital load distribution control

Author(s):  
S. Huth
2021 ◽  
Vol 252 ◽  
pp. 02013
Author(s):  
Yu Chen ◽  
Hongcheng Ding ◽  
Junwei Zhang ◽  
Ganghui Ding ◽  
Jun Cui ◽  
...  

It is an effective measure for power enterprises to improve the voltage level of the system by raising and lowering the tap position of the main transformer. For the parallel operation of the main transformer, the whole process of adjusting the tap must strictly meet the conditions of parallel operation. Aiming at a case of backup protection action of main transformer caused by improper implementation of voltage regulation measures, this paper analyzes the uneven load distribution and increase of reactive power loss caused by improper adjustment of tap, and the analysis results are verified by PSCAD.


1942 ◽  
Vol 148 (1) ◽  
pp. 42-52
Author(s):  
Paul G. Kaufmann

The paper deals with the load distribution between a number of boilers operating in parallel, with a view to obtaining minimum fuel consumption. The application of the theory of minima leads to a graphical solution, and it is demonstrated that maximum plant efficiency can generally be obtained only when all boilers share in the load fluctuations to an extent depending on the input-output characteristics of the various boilers and on the momentary load. The division of a plant into groups of boilers operating at base load and fluctuating load, respectively, is generally not economical. Automatic boiler control not only increases the operating efficiency of the individual boiler but can be used also for maintaining the most economical load distribution between the units, and thereby also raises the efficiency of the plant as a whole. The paper also discusses how many and which units should be used to cover a given load range, and when a boiler ought to be banked or connected to the line again. This depends upon the ratio between standby and operating periods; but generally it will be more economical to operate all boilers down to their minimum load than to bank some of them. The same principles of load distribution can be applied to the parallel operation of any kind of machines other than boilers.


2008 ◽  
Vol 46 (01) ◽  
Author(s):  
N Billecke ◽  
N Raschzok ◽  
H Morgul ◽  
C Leist ◽  
K Schmitt ◽  
...  

2013 ◽  
Vol 41 (4) ◽  
pp. 232-246
Author(s):  
Timo Völkl ◽  
Robert Lukesch ◽  
Martin Mühlmeier ◽  
Michael Graf ◽  
Hermann Winner

ABSTRACT The potential of a race tire strongly depends on its thermal condition, the load distribution in its contact patch, and the variation of wheel load. The approach described in this paper uses a modular structure consisting of elementary blocks for thermodynamics, transient excitation, and load distribution in the contact patch. The model provides conclusive tire characteristics by adopting the fundamental parameters of a simple mathematical force description. This then allows an isolated parameterization and examination of each block in order to subsequently analyze particular influences on the full model. For the characterization of the load distribution in the contact patch depending on inflation pressure, camber, and the present force state, a mathematical description of measured pressure distribution is used. This affects the tire's grip as well as the heat input to its surface and its casing. In order to determine the thermal condition, one-dimensional partial differential equations at discrete rings over the tire width solve the balance of energy. The resulting surface and rubber temperatures are used to determine the friction coefficient and stiffness of the rubber. The tire's transient behavior is modeled by a state selective filtering, which distinguishes between the dynamics of wheel load and slip. Simulation results for the range of occurring states at dry conditions show a sufficient correlation between the tire model's output and measured tire forces while requiring only a simplified and descriptive set of parameters.


Author(s):  
Adyson Magalhaes Maia ◽  
Yacine Ghamri-Doudane ◽  
Dario Vieira ◽  
Miguel Franklin de Castro

Author(s):  
V. E. Perekutnev ◽  
V. V. Zotov

Operation of inhaul rubber steel cables in vertical mine hoisting is discussed. The research in the field of mine hoisting is reviewed, and the further R&D directions are identified. Some studies concern life extension of hoisting ropes. One of the promising trends seems to be application of belt pullers as inhaul cables, which can essentially enhance mine hoist efficiency. In the meanwhile, capabilities of rubber steel cables suffer from deficient attention. The performance capabilities of rubber steel cables of top manufacturers (Promkanat and SAG) are compared, and application ranges in vertical mine hoisting are determined for such cables. It is found that the Polish manufacturer’s rubber steel cables offer a wider range of application. The analysis shows that rubber steel cables can be used as inhaul cables of vertical mine hoisters. Rubber steel cables possess suitable characteristics and are capable to elevate considerable loads to various hoisting heights. In particular, the existing rubber steel cables ensure carrying capacity of hoists up to 20-25 t at the hoisting heights to 400-500 m and sometimes can elevate skips with tonnage of 10 t to a height up to 1000 m and more. The further feasibility study of operation of inhaul steel rubber cables in hoisting units should address motion stability of a puller on a driving drum, load distribution in ropes of base of rubber steel cables, validation of hoister design, adjustability of rubber steel cable length during its operation, etc.


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