Can "in order to keep" be used in place of "allowing"?
Solution 1:
Using participle clauses , which are non-finite, that is have no associated subjects, is often legitimate, convenient and succinct, but can give rise to ambiguities in complicated cases like this one.
An alternative approach commonly used in spacecraft is to divert surplus PV power into a resistive load, allowing the panel to operate continuously at its peak power point.
can mean either (probably the default reading, admittedly)
[A] An alternative approach commonly used in spacecraft is to divert surplus PV power into a resistive load; this diversion of power enables the panel to operate continuously at its peak power point.
[the diverting strategy does the enabling], or
[B] An alternative approach commonly used in spacecraft is to divert surplus PV power into a resistive load, while leaving the panel to carry on operating continuously at its peak power point.
[the astronauts leave the panel operating at full power].
While these probably do not differ significantly in overall meaning in this case (and it is not the job of ELU to comment on the feasibility of the operation involved), participle clauses need to be handled with care, and replaced if there is any hint of ambiguity.
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Your first suggestion doesn't make sense; do you mean 'adding thus'? Yes; adding 'thus' (or better, 'thereby') before 'allowing' disambiguates, forcing reading [A].
Your suggested paraphrase may get the main point across, but is by no means a felicitous precise rewrite.