| 摘要 |
PURPOSE:To hold the operation point of a solar battery to a place around a really optimum operation point at that time by calculating the average value of output voltage at every prescribed period and periodically substituting virtual optimum operation voltage for the average value at the time of increasing/decreasing the change width of a control target value in accordance with a difference between the output voltage measured value and virtual optimum operation voltage. CONSTITUTION:Maximum power point tracking (MPPT) control by a hill climbing method, which a microcomputer 24 executes, is constituted by a reference setting processing for periodically updating virtual optimum operation voltage VSop and a control target setting processing for setting a current amplitude command lamp based on virtual optimum operation voltage SVop, and it is executed at every 50ms, for example. In the routine of the reference setting processing, the output voltage Vi of the solar battery 10 is measured at the period of 500ms, for example, and virtual optimum operation voltage SVop is updated whenever about thirty pieces of measured values are obtained. Thus, virtual optimum operation voltage becomes a value approximated to real optimum operation voltage, and the change width of the control target can be optimized. |
