This paper presents an innovative method to measure the dynamic control ability of maximum power point tracking for PV inverters under the condition of irradiance fluctuation. The PV array I-V curve simulator is a kind of indoor testing facility and easy to be adopted by industries. Basic functions are given by a specially designed PV array I-V curve simulator composed of the active power load. Most of the parameters are controllable by sophisticated software with capability of treating a lot of I-s data for a very long period of time. In this paper, detailed structure of the equipment is described and test examples are also given by using a commercial PV inverter. (C) 2002 Elsevier Science B.V. All rights reserved.