Abstract: A method and system of controlling a power converter coupled between a power generator and an electric grid. The method comprises detecting a grid disturbance voltage dip event while the power converter operates in a first phase locked loop (PLL) control mode that establishes a state of synchronization with the electric grid, the power converter electrically coupled to either motor drive inverter or grid-tie inverter, detecting a loss of the state of synchronization with the electric grid in conjunction with progressive charge depletion from a charged state of the dc-link capacitors, switching the converter to a diode mode of operation, switching from the first PLL control mode to a second PLL control mode of operation of the power converter, and re-establishing the state of synchronization to timely pre-empt progressive depletion of charge from the dc-link capacitors while under the second PLL control mode of operation of the power converter.

Abstract: A method and system of controlling a power converter operatively coupled with an electric grid, includes: operating the power converter in a direct power control mode with a dynamic switching table, the dynamic switching table including a group of converter space vectors and switching rules associated with the grid voltage and the dc-link voltage of the power converter; detecting abnormalities in the grid voltage and/or the converter dc-link voltage due to a grid fault event relative to their nominal operating conditions; determining a group of crossover angles for a group of converter vectors including the nearest three vectors to a grid voltage vector location inside a hexagonal space vector diagram; dynamically selecting a proper vector based on algorithmic feedforward of the group of crossover angles to dynamically construct the dynamic switching table; and controlling an output power of the power converter.

Abstract: A method and system of controlling a power converter coupled between a power generator and an electric grid. The method comprises detecting a grid disturbance voltage dip event while the power converter operates in a first phase locked loop (PLL) control mode that establishes a state of synchronization with the electric grid, the power converter electrically coupled to either motor drive inverter or grid-tie inverter, detecting a loss of the state of synchronization with the electric grid in conjunction with progressive charge depletion from a charged state of the dc-link capacitors, switching the converter to a diode mode of operation, switching from the first PLL control mode to a second PLL control mode of operation of the power converter, and re-establishing the state of synchronization to timely pre-empt progressive depletion of charge from the dc-link capacitors while under the second PLL control mode of operation of the power converter.

Abstract: A method and system of controlling a power converter coupled between one of a motor drive inverter and a grid-tie inverter within an electric grid. The method comprises operating the power converter in a first PLL control mode that establishes a state of synchronization with the electric grid, detecting a grid disturbance voltage dip event; keeping the power converter synchronized and preserving charge of a set of dc-link capacitors, switching from the first PLL control mode to a second PLL control mode of operation of the power converter to obtain fast re-synchronization after dip period ends, and reverting to operation in the first PLL control mode upon re-establishing of the state of synchronization.