Fundamental wave dq coordinate system-based PR harmonic compensation method

Abstract

The invention discloses a fundamental wave dq coordinate system-based PR harmonic compensation method. The method comprises the steps of: designing a discrete domain-based high-pass digital filter soas to obtain a to-be-compensated high-frequency harmonic component; determining a corresponding frequency, in a fundamental wave dq coordinate system, of the to-be-compensated high-frequency harmoniccomponent at each time; aiming at restraining abnormal peak values, determining delay compensation phases of a fundamental wave PR controller and a harmonic PR controller; and designing a proportionality coefficient of the fundamental wave PR controller on the basis of a nearest distance between an Nyquist map and (-1, 0j), determining harmonic coefficients of the fundamental wave and harmonic PRcontrollers according to the proportionality coefficients of the fundamental wave and harmonic PR controllers. The method is capable of effectively compensating high-frequency harmonic waves, therebyrestraining the distortion of power grid current, decreasing the quantity of PR controllers, lightening the operation loads of systems and avoiding the problem that compensation current exceeds an APFcurrent capacity.

Description

technical field [0001] The invention relates to the technical field of new energy grid connection, in particular to a PR harmonic compensation method based on a fundamental wave dq coordinate system. Background technique [0002] Since the 20th century, with the rapid development of power electronic technology, various power electronic devices have been widely used in power systems, industries, transportation, and households, and the resulting harmonic problems have become increasingly serious. Power electronic devices generate harmonics, and the harm to the public grid includes: ① Harmonics cause additional harmonic losses to components in the grid, reducing the efficiency of power generation, transmission, and power consumption equipment; ② Harmonics affect the performance of various electrical equipment Normal operation will cause mechanical vibration of the motor, severe local overheating of the transformer, and aging of the insulation; ③ Harmonics will cause local paral...

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Problems solved by technology

[0005] Selective harmonic compensation can be based on the static coordinate system, each harmonic dq coordinate system, or the fundamental dq coordinate system, but as far as the first two coordinate systems are concerned, the more harmonics selected for compensation, the corresponding controller There are more, the complexity of the system becomes stronger, and the calculation load becomes larger, and the selective harmonic compensation based on the fundamental dq coordinate system can halve the number of controllers, and the controller can choose PI controller, PR controller or VPI Controller, in which PI controller needs to decouple the dq quantity in the process of use, the implementation process is more complicated, and it is difficult for VPI to achieve the stability of high-frequency control, so the PR controller is the best choice

[0006] So far, the design of APF harmonic compensation has basically adopted non-selective harmonic compensation technology, which is prone to problems of insufficient equipment compensation capacity and low robustness; in addition, most compensation controllers are designed based on The dq coordinate system or static coordinate system of each harmonic does not take into account the complexity of the system and the operational efficiency of the digital controller. The design of the control either does not consider the system delay, or the delay compensation is insufficient, so that the harmonic compensation occurs The abnormal peak value of the closed loop leads to poor harmonic compensation effect of the system

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