Harmonic suppression method and device for inverter

• Main Authors: XU LI, YUAN SHUAI, WANG JINCHENG, LI SHIJUN, LI BAILONG, SHU CHENGWEI, LIAO XIAOJUN
• Format: Patent
• Language: English
• Published: 30.12.2015
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; CONTROL OR REGULATION THEREOF; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERATION; REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGYGENERATION, TRANSMISSION OR DISTRIBUTION; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE

The embodiment of the invention provides a harmonic suppression method and device for an inverter. The harmonic suppression method includes the steps that according to the three-phase output current Ia, Ib and Ic, zero-sequence current Io is obtained through calculation; according to the zero-sequence current Io, in reference to a set current value, a closed-loop control regulating variable is obtained through calculation; the closed-loop control regulating variable is output to duty ratio output of three-phase PWM for control. Through closed-loop control over the zero-sequence current, the defect that a traditional LCL type filter has a resonance peak value, so that a harmonic component is too high can be effectively overcome, and then the harmonic content of grid connection current is effectively reduced; compared with an improved LCL filter, harmonic suppression is achieved without connecting damping resistors in series, the overall efficiency is improved, and certain practical value and reference value are achieved in the photovoltaic field.