In IPXACT file, there can be multiple views of the IP e.g. for a hard IP, there can be a simulation view and an emulation view. The HDL files corresponding to these views have some parameters which are common while some are usage specific and hence are different.
In IP-XACT, there is no way to represent the different parameters as there can be only one set of model parameters. This can be a big problem as it can also lead to non-compilable RTL generation because the parameter map during instantiation does not correspond to the parameters in actual IP RTL.
One way to handle this is to create a configuration that would contain a group of parameters that would be the core set in all views. Then each view could add any additional parameters that it needed.