In WinPE you have to enable TPM support by "drvload x:\winows\inf\tpm.inf" command, then you can use "manage-bde.exe -tpm -t" to enable TPM and "manage-bde.exe -tpm -o password" to take ownership - this is for WinPE3.
For WinPE2 change "manage-bde.exe" for "cscript manage-bde.wsf", syntax remain same.
Regards,
Martin