Hey @Hakesh_Kolukonu!
If you're looking to download a plotly chart from a custom component you'll likely need to use a more involved method like the one @everett_smith describes above. Since you're using a combination of the two the best options I'm thinking of are to:
- Download each chart individally
- Use a JS query to generate the plotly JSON you need to render your custom component charts using the built-in component (more on that here)
- Copy the plotly JSON for the data source and layout into a transformer and use it as inputs for the custom component model to render built-in charts in your then download everything together from a single custom component
Hopefully one of those can work for your use case 
Otherwise, it is a known request to be able to download custom, HTML, and iFrame components using utils.downloadPage. Though it's currently in the backlog and there aren't concrete plans to implement it, we can try and let you know here if it does get included!