The invention discloses an MPPT (
maximum power point tracking) control device and an MPPT control method of a
photovoltaic inverter. The MPPT control method includes the steps: A, sampling direct-
current voltage Ux and
direct current Ix of a direct-current side of the
photovoltaic inverter, and computing input power Px of the direct-current side of the
photovoltaic inverter; B, judging whether the direct-
current voltage Ux is not larger than a
voltage minimal value U1 or not, if so, updating the
voltage minimal value U1 and corresponding input power P1 and switching to D, and otherwise switching to C; C, judging whether the direct-
current voltage Ux is not smaller than a
voltage maximum value U2 or not, if so, updating he voltage maximum value U2 and corresponding input power P2 and switching to the D, and otherwise switching to E; D, computing a voltage result value U; and E, sending PWM (pulse-width modulation) signals of switches in the photovoltaic
inverter according to the voltage result value U. The MPPT control method is simple in sampling
MPPT algorithm, easy to implement, rapid in
processing, stable in control and capable of improving use efficiency of solar cells.