It is a disadvantage that PV power generation is only useful for clear daytime. However, a new 24 hours of application in an extended area can be added by active utilization of potential ability of PV power conditioner. For this purpose, a new multi-functional power conditioner was developed, which has a smoothing function to reduce PV output variation and load fluctuation, and also has additional function to compensate harmonics current and reactive power caused by customer's load. As a result of indoor testing, a reduction rate of around (1)/(20) for harmonics current and reactive power were achieved. In addition, the reduction rate around (1)/(10) for smoothing of PV output variation and load fluctuation were verified. The work was promoted by NEDO as part of the New Sunshine Project in Japan. (C) 2002 Elsevier Science B.V. All rights reserved.