SAO PAULO, April 15 (Reuters) - Three companies have submitted offers to participate in the privatization auction of Brazilian power generator EMAE, which is scheduled to happen on Friday, a source familiar with the matter told Reuters on Monday.

EMAE is currently controlled by the state of Sao Paulo, which owns 97.6% of its ordinary shares and plans to raise at least 779.8 million reais ($150.26 million) by selling its stake in the firm.

O Estado de S. Paulo newspaper reported earlier in the day that French power giant EDF, Matrix Energia and investment fund Phoenix had all presented bids for the auction.

A second source told Reuters that Matrix, a joint venture between asset manager Prisma Capital and a subsidiary of Switzerland-based Duferco Group, would indeed participate in the privatization auction.

EMAE owns and operates a hydraulic and energy generating system that stretches across Sao Paulo state. Its main asset is the Henry Borden hydroelectric plant, with 889 megawatts (MW) of power.

EMAE also has Latin America's largest utility Eletrobras as a relevant shareholder with 64.8% of its preferred shares. The Brazilian power giant, however, has expressed interest in divesting the asset in the future. ($1 = 5.1895 reais) (Reporting by Leticia Fucuchima; Editing by Angus MacSwan)