# Iterpolation shows wrong results

2 ビュー (過去 30 日間)
K 2024 年 1 月 14 日
コメント済み: K 2024 年 1 月 22 日
Hello
I have a major problem with my results that I can't seem to find its reason
My model beginns with an electrical loads which is supplied by a synchronous generator. the generator gets its power via an asynchronous motor (galvanic isolation of an island grid)
and this is the electrical load, connected to the generator, which was interpolated using the interp1 spline method and goes to a 1D lookup table
the values of the 1D table are measurment points each 30s and where interpolated to points each 10s (1 sample point in matlab=10s --> total of 90 sample point) and working with a finer interpolation would last so long
ah shown the plot looks smooth and the torque od the induction motor looks fine so far
the problem is the speed which has these semi-intervall between each two points (like between 18 and 19)
what I would like to achieve is what I've drawn with a blue line
I guess it's a problem related to the interpolation right? I don't know why I have these semi-Intervall, and the moving average block didn't help
the lookup table has the following setting
I have the following questions:
• is it a solver problem? I used fixed step discrete size 1e-5
• is it an interpolation problem?
• if fixing the model isn't possible, is there any other war?
I'd be gratfull for any suggestions or ideas
regards,
##### 2 件のコメントなしを表示なしを非表示
vidyesh 2024 年 1 月 22 日
Can you attach the simulink model?
K 2024 年 1 月 22 日
thank you
the problem was clearly a step size mistake. I implemented each measurment point to a natural number (1,2,3...) which made the plot have these semi interval. when I implemented each measurment point in step size of 0.1 (like 1.1;1.2;1.3...) I got better plots, which takes me to my second question (that I posted after):
how do I know the step size of a discrete model? I used all the same parameters of the Electric engine dyno model (https://de.mathworks.com/help/sps/ug/electric-engine-dyno.html?searchHighlight=dyno&s_tid=srchtitle_support_results_1_dyno)
I think it has something to do with the "Control sample time " and "Fundamental sample time " for FOC, to which I didn't find answers in documentation
new step size with which I implemented the measurments value is 0,1 which happens to be the ratio (Fundamental sample time / Control sample time).
it also worked with step size 0,2 which is (Fundamental sample time*10*switch frequency) so I guess these are the parameters that defines the step size.
can you help me understand the step size of the engine dyno model?
regards

サインインしてコメントする。

### カテゴリ

Help Center および File ExchangeMotor Drives についてさらに検索

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by