According to a Japanese dictionary,
性格 refers to an individual's emotional propensity, whereas
人格 refers to his/her total personality as a human.
(You know, those two are quite similar each other in its meaning, but the usage is sometimes not interchangeable.)
①彼は素晴らしい性格(〇人格)の持ち主だ。
②あの人は性格(△人格)が良い/悪い。
③人格(×性格)を磨く。
④めんどくさがりな性格(×人格)。
⑤あの人は人格者(×××性格者)だ。