A New Kalman-Filter-Based Harmonic Current Suppression Method for the Virtual Oscillator Controlled Grid-tied Inverter

Virtual Oscillator Control (VOC) is an advanced nonlinear grid-forming controller used for power electronics interfaced distributed generation (DG). In order to improve the reliability of voltage source converter connecting to the disturbance grid, a feedback method with enhanced virtual impedance had been inserted into the control loop of the VOC-based inverter to suppress grid-injected harmonic currents. In this paper, a new grid-injected harmonic current suppression strategy with estimated voltage feedforward is proposed for a VOC-based voltage source inverter (VSI) connected to the distorted electrical grid. To achieve the control target, the Kalman-Filter is adopted to estimate the harmonic components of the grid voltage at the point of common coupling (PCC) and insert them to the feedforward control loop of the VOC-based inverter. Compared with the traditional VOC with enhanced virtual impedance method, the proposed control strategy has a slightly better ability to suppress the grid-injected harmonic current. A 3 kW/3-phase/120 V experimental prototype system designed on the DSPACE DS1202 platform has been developed to verify the effectiveness of the proposed control strategy.