Yes it's the past participle of encourage.
It's also the simple past tense of encourage. Regular verbs have the same simple past and past participle.
The past participle is "encouraged"
"Encouraged" is the simple past and past participle of the verb "encourage".
The verb encourage has the present participle encouraging, which as an adjective can have the adverb form encouragingly.
Being is the present participle. The past participle is been.
The past participle of do is done. The past participle of have is had.
The present participle is beating. The past participle is beat.
Present participle - winding Past participle - winded
The present participle is "sowing" and the past participle is "sown".
Begun is the past participle, and beginning is the present participle.
The past participle of am is been. Not does not have a past participle
The present participle is swelling. The past participle is swelled.
The past participle is proceeded. The present participle is proceeding.