3results about How to "Guaranteed modeling accuracy" patented technology

The present invention discloses a unified mathematical modeling method for an open-circuit fault of a three-level photovoltaic inverter, and the steps include: 1. according to the characteristics of the DC side voltage fluctuation when the three-level photovoltaic inverter is in maximum power point tracking operation, a mathematical expression of the DC side voltage of the three-level photovoltaic inverter is obtained; 2. according to different working conditions and current paths of the main circuit power switch device of the three-level photovoltaic inverter, a switch function expression under the corresponding fault condition is obtained, and finally a unified open-circuit fault switch function expression and an expression of the output phase voltage of the three-level photovoltaic inverter are obtained. The present invention can quickly establish a correct unified mathematical model of the open-circuit fault of the three-level photovoltaic inverter through the switch function modeling method, thereby solving the problems of the large number of modules, large amount of calculation, poor flexibility of switching simulation of different types of faults, etc. in the existing three-level photovoltaic inverter fault simulation circuit modeling method, and reducing the workload of modeling and its simulation working time.

The invention relates to a method for generating a verification model through any-order ray tracing. The method comprises the following steps: inputting and determining an incident point coordinate, an N-order reflection point coordinate and an emergent point coordinate after ray escape after the latest reflection; calculating an incident direction and a reflection direction of the ith reflection, and calculating a normal vector on a reflection point of the ith reflection; establishing a reflection local coordinate system of i-th reflection by taking the reflection point as an original point; and generating a model or a grid of the reflection system according to the reflection local coordinate system. According to the method, the accuracy of a ray tracing verification model is remarkably improved, the method can be adapted to any ray reflection scene of a positive integer order, and a high-fidelity model support is provided for design of various complex optical reflection systems and ray tracing simulation.

The application provides a three-dimensional model construction method and system for topographic survey, and belongs to the technical field of model construction. The method comprises the following steps: segmenting satellite images of a target survey area based on the complexity of the terrain to obtain complex terrain areas and open terrain areas; obtaining laser scanning data of the complex terrain areas and low-altitude image data of the open terrain areas; fusing the laser scanning data and the low-altitude image data to obtain a target data set corresponding to the target survey area; constructing a regular grid model corresponding to the target survey area based on the target data set; constructing an irregular triangular grid model corresponding to the target survey area based on the laser scanning data; and fusing the regular grid model and the irregular triangular grid model to obtain a three-dimensional model of the target survey area. The three-dimensional model construction method and system for topographic survey can improve the modeling accuracy.