The invention provides a direct power prediction control method based on three-phase six-switch
rectifier load current observation, and discloses a direct power prediction control technology for three-phase
rectifier load current observation. The direct power prediction control method comprises the steps of: A, measuring three phases of currents, a three-phase
power grid voltage and a DC side
capacitor voltage through a
current sensor and a
voltage sensor respectively; B, calculating voltage vectors corresponding to eight kinds of switch combinations (000, 001, 010, 100, 011, 101, 110, 111) through the measured DC side
capacitor voltage; C, passing a given
DC voltage through a filter to obtain an instantaneous reference voltage of a sampling period at present, and acquiring an instantaneous reference value of active power according to a DC side and AC side power
conservation principle, wherein the reference value of active power is calculated by adopting an observer to estimate a load current; D, predicting active power, reactive power and
capacitor voltages corresponding to eight voltage vectors of a
rectifier according to the measured
phase currents and the phase voltages; E, and calculating a corresponding cost function F, and applying a switching state corresponding to the
voltage vector with the minimal cost function value to the rectifier. The direct power prediction control method is applicable to various kinds of three-phase rectifiers and active filters.