  In this paper, we introduce a sequential variational mode decomposition
method to separate non-stationary mixed signals successively. This method is
inspired by the variational method, and can precisely recover the original
components one by one from the raw mixture without prior knowing or assuming
the number of components. And in such a way, the mode number also can be
determined during the separation procedure. Such character brings great
convenience for real application and differs from the current VMD method.
Furthermore, we also conduct a principal elongation for the mixture signal
before the decomposing operation. By applying such an approach, the end effect
can be reduced to a low level compared with the VMD method. To obtain higher
accuracy, a refinement process has been introduced after gross extraction.
Combined these techniques together, the final decomposition result implies a
significant improvement compared with the VMD method and EMD method.
