Direct power prediction control method based on three-phase six-switch rectifier load current observation

Abstract

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.

Description

technical field [0001] The invention belongs to the field of rectification, and in particular relates to a model predictive control method for direct power control with a load current observer under the topology of a three-phase power converter. Background technique [0002] In recent years, the rectifier composed of six-switch three-phase fully-controlled power electronic devices has many advantages such as controlling the bidirectional flow of energy, controllable power factor, good DC voltage regulation performance, and sinusoidal input current. , wind energy and other renewable energy grid-connected power generation, active power filter, and frequency conversion speed regulation and other systems have been widely used. [0003] Among the many patents and literatures on the control strategy of the three-phase six-switch rectifier system, the general methods are divided into three categories: one is to use the voltage vector oriented control (VOC), and the coordinate axis ...

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Problems solved by technology

[0003] Among the many patents and literatures on the control strategy of the three-phase six-switch rectifier system, the general methods are divided into three categories: one is to use the voltage vector oriented control (VOC), and the coordinate axis is oriented to the voltage vector by rotating the coordinate transformation , to obtain decoupling control of active power and reactive power, but this type of algorithm requires coordinate transformation and modem, and its control parameters are too many to be adjusted; the other type is direct power control (DP

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