A method of back-stepping direct power control for grid-connected converters

Abstract

The invention discloses an inverse direct power control method of a grid connection converter. According to the method, a reverse algorithm is combined with a DPC (Dynamic Power Control) technology; firstly an active power reference value and a change rate thereof are obtained through a voltage outer loop reverse controller and then input into a power inner ring reverse controller together with a passive power reference value, so a voltage reference value output by the grid connection converter can be calculated, and a switch signal is obtained through modulation of a SVPWM (Space Vector Pulse Width Modulation) module. The entire control process is performed in a static coordinate system without changing a rotary coordinate; only three adjustable parameters are required to be adjusted to realize progressive tracking of voltage of a direct current bus of the converter, meanwhile effective control of active and passive power and quick response of the system are realized, and the control structure is extremely concise. The current harmonic and the power fluctuation can be reduced while the superior dynamic performance of the conventional DPC is inherited, so the voltage of the direct current bus is more stable, constant switching frequency is obtained, and good stable and dynamic performance is realized.

Description

technical field [0001] The invention belongs to the technical field of electric power equipment control, and in particular relates to a back-pickup direct power control method of a grid-connected converter. Background technique [0002] With the aggravation of the energy crisis and the enhancement of people's awareness of environmental protection, the development and utilization of renewable energy such as wind power and photovoltaic power generation, as well as distributed power generation technology and high-voltage direct current transmission technology (HVDC) have achieved unprecedented development. The voltage-type grid-connected converter is widely used in the fields of renewable energy distributed power generation and high-voltage direct current transmission because of its good input and output characteristics, independent adjustment of active power and reactive power, etc. It also has a very important role and status. [0003] Vector control (VC) and direct power co...

AI Technical Summary

Problems solved by technology

DPC based on PI controller and space vector modulation (SVM) can obtain smaller power fluctuation and constant switching frequency, but the introduction of PI controller makes it have the same problems as VC. In addition, this method has no effect on the mathematical model The parameter dependence degree is high, so the robustness is not strong

Predictive direct power control (P-DPC) that selects three vectors in one sampling time can also obtain better steady-state and dynamic performance, and the switching frequency is constant, but it needs to calculate the action time of the three vectors in real time, and the calculation amount is relatively large. Large, vector selection is more complicated

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