The full control system of a grid-connected current-controlled voltage-source inverter (CC-VSI) has been designed and\r\nimplemented on a field-programmable gate array (FPGA). Various control functions and implementation methods are described\r\nand discussed. The practical viability of the system is evaluated in an experimental setup, where a VSI supplies 30kW into the local\r\ngrid at 400V. A phase-locked loop (PLL) is used for grid phase tracking and evaluated for simulated abnormal grid conditions.\r\nPower factor is kept at unity, and the implemented control system is stressed with step responses in the supplied active power. A\r\nmoving-average filter is implemented to reduce the effects of noise and harmonics on the current control loops. A coupling between\r\nactive and reactive power flow is observed for the step responses but may be ignored in this context. The proposed system is fully\r\ncomparable with more conventional microprocessor-based control systems.
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