A power conversion system, comprising: an AC input coupleable to receive AC input power from a power source; a rectifier, including a plurality of AC input terminals, first and second DC output terminals, and a plurality of rectifier switching devices (S1-S6) individually coupled between a corresponding one of the AC input terminals and one of the first and second DC output terminals; a filter circuit coupled between the AC input and the rectifier; an inverter, including first and second DC input terminals, a plurality of AC output terminals, and a plurality of inverter switching devices (S7-S12) individually coupled between a corresponding one of the DC input terminals and one of the AC output terminals; an intermediate DC circuit including a capacitor coupled between the first and second DC output terminals of the rectifier; and a controller operative in a first mode to provide rectifier switching control signals to operate the rectifier switching devices (S1-S6) to regulate a DC voltage of the intermediate DC circuit according to a setpoint value, and to provide inverter switching control signals to operate the inverter switching devices (S7-S12) to convert DC power from the intermediate DC circuit to provide AC output power to the AC output terminals; wherein the controller is operative in a second mode to provide the rectifier switching control signals to turn the rectifier switching devices (S1-S6) off, and to provide the inverter switching control signals to operate the inverter switching devices to regulate the DC voltage of the intermediate DC circuit, wherein the controller is operative to detect clearance of an abnormal grid condition, and to change from the second mode to the first mode in response to detection of clearance of the abnormal grid condition, wherein the controller is further operative to: measure the DC voltage in response to detection of clearance of the abnormal grid condition, initially set the setpoint value to the measured DC voltage value when changing from the second mode to the first mode, and ramp the setpoint value to a nominal setpoint value after changing from the second mode to the first mode. an AC input coupleable to receive AC input power from a power source; a rectifier, including a plurality of AC input terminals, first and second DC output terminals, and a plurality of rectifier switching devices (S1-S6) individually coupled between a corresponding one of the AC input terminals and one of the first and second DC output terminals; a filter circuit coupled between the AC input and the rectifier; an inverter, including first and second DC input terminals, a plurality of AC output terminals, and a plurality of inverter switching devices (S7-S12) individually coupled between a corresponding one of the DC input terminals and one of the AC output terminals; an intermediate DC circuit including a capacitor coupled between the first and second DC output terminals of the rectifier; and a controller operative in a first mode to provide rectifier switching control signals to operate the rectifier switching devices (S1-S6) to regulate a DC voltage of the intermediate DC circuit according to a setpoint value, and to provide inverter switching control signals to operate the inverter switching devices (S7-S12) to convert DC power from the intermediate DC circuit to provide AC output power to the AC output terminals; wherein the controller is operative in a second mode to provide the rectifier switching control signals to turn the rectifier switching devices (S1-S6) off, and to provide the inverter switching control signals to operate the inverter switching devices to regulate the DC voltage of the intermediate DC circuit, wherein the controller is operative to detect clearance of an abnormal grid condition, and to change from the second mode to the first mode in response to detection of clearance of the abnormal grid condition, wherein the controller is further operative to: measure the DC voltage in response to detection of clearance of the abnormal grid condition, initially set the setpoint value to the measured DC voltage value when changing from the second mode to the first mode, and ramp the setpoint value to a nominal setpoint value after changing from the second mode to the first mode. measure the DC voltage in response to detection of clearance of the abnormal grid condition, initially set the setpoint value to the measured DC voltage value when changing from the second mode to the first mode, and ramp the setpoint value to a nominal setpoint value after changing from the second mode to the first mode.