Predictive control specified harmonic suppression switch strategy with low switching frequency characteristic

Abstract

The invention discloses a predictive control specified harmonic suppression switch strategy with a low switching frequency characteristic, and the strategy comprises the steps: obtaining a system prediction model, so as to carry out the prediction of a state of a controlled object at a future moment; extracting fundamental waves and harmonic amplitudes of the controlled object at future moments; calculating a cost function, and selecting a switching state enabling the cost function to be minimum to be fed back to the control system; at the next sampling moment, the above process is circulated to obtain the on-off state of the complete period, and the suppression requirement of the control system on the specified subharmonic is met; the predictive control algorithm provided by the invention can effectively suppress, even-order harmonics are basically eliminated, and the switching frequency of the system can be reduced to 700Hz while low-order harmonics are ensured to be effectively suppressed, so that the effect equivalent to that of an SHEPEM strategy can be achieved, and harmonic waves of an output waveform of an inverter are effectively suppressed while the switching frequency is reduced; and compared with online calculation, the real-time performance is better, and the burden of hardware resources can be effectively reduced.

Description

technical field [0001] The invention relates to the field of inverter control, in particular to a predictive control specified harmonic suppression switching strategy with low switching frequency characteristics. Background technique [0002] In recent years, distributed power generation systems based on renewable energy such as wind energy and solar energy have gradually attracted attention due to their advantages of cleanliness, economy, and sustainable development, and have become a research hotspot. As a small power generation and distribution system that organically integrates distributed power supply devices, energy storage systems, and various load devices, microgrid can make full use of distributed renewable energy and better develop its power generation potential. The microgrid can operate independently from the island of the large power grid. The inverter is an important interface between the island microgrid and the independent load. Mainly by controlling the inve...

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the disadvantages of poor real-time performance and low dynamic performance of the algorithm in the SHEPWM modulation strategy, and propose a specified harmonic suppression switching strategy based on predictive control method, so that the inverter can operate at a low switching frequency While running, it can suppress harmonics and improve the dynamic performance of the control system

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