Patent ID: 9397549
Filing Date: 2016-07-19
CPC Classification: H02M

Claim Text:
1. A power conversion system for controlling harmonics, comprising: a DC terminal; a DC-AC power converter, electrically coupled to the DC terminal and electrically coupled to an AC terminal via a transformer; and a digital operational unit, electrically coupled to the DC-AC power converter and the transformer, for controlling a power output of the DC-AC power converter by using a control strategy; wherein one side of the transformer being coupled to the AC terminal is called to an AC side, and the digital operational unit uses the Fourier transform (FT) to calculate a current harmonics amount of the AC side, and the digital operational unit adds a harmonics compensation strategy to decrease harmonics elements generated from an actual current; wherein the control strategy of the digital operational unit comprises: receiving a 3-phase voltage feedback signal and a 3-phase current feedback signal from the AC terminal, and preliminary defining a current decoupling compensation parameter; providing a 3-phase reference coordinates to a current instruction of converting 3-phase to 2-phase and a voltage instruction of converting 2-phase to 3-phase; feeding the current instruction of converting 3-phase to 2-phase back to an input terminal, and combining the current instruction and a d-axis current instruction and a q-axis current instruction; respectively controlling the d-axis current and the q-axis current, compensating a d-axis voltage and a q-axis voltage and combining the current decoupling compensation and the harmonic compensation strategy, and controlling the PWM by the 2-phase to 3-phase voltage instruction.