Abstract: A method for operating a multi-level bridge power converter includes arranging a plurality of switching devices including at least four inner switching devices and at least two outer switching devices in an active neutral point clamped topology. The method also includes determining whether any of the switching devices is experiencing a failure condition by implementing a failure detection algorithm. The failure detection algorithm includes generating a blocking state logic signal by comparing a switching device voltage and a threshold reference voltage for each of the switching devices, determining an expected voltage blocking state for each of the switching devices based on gate drive signals of the switching devices and an output current direction, and detecting whether a failure condition is present in any of the switching devices based on the blocking state logic signals and the expected voltage blocking states of the switching devices.

Abstract: A power conversion assembly includes a power converter having a plurality of switching devices, a power source electrically coupled to the power converter, and a direct current (DC) filter circuit bridging the power converter and the power source. The DC filter circuit includes a DC link having a positive rail, a negative rail, and a capacitor bank. The capacitor bank includes a first set of capacitors being a first type of capacitors and a second set of capacitors being a different, second type of capacitors. Each capacitor in the first set of capacitors is positioned closer to a respective switching device of the plurality of switching devices than a corresponding capacitor of the second set of capacitors to minimize impedance between each capacitor in the first set of capacitors and the respective switching device such that a majority of ripple current from the plurality of switching devices passes through the first set of capacitors.

Abstract: A method for controlling a voltage source power converter of a renewable energy power conversion system includes providing the voltage source power converter having, at least, a rotor-side converter and a line-side converter. The method also includes generating, via a converter controller, a first set of switching pulses based on a third-harmonic phase opposition carrier-based pulse width modulation (PO_CB_PWM) scheme. Further, the method includes generating, via the converter controller, a second set of switching pulses based on a third-harmonic in phase carrier-based pulse width modulation (IP_CB_PWM) scheme. As such, the method includes implementing, via the converter controller, a pulse-width modulation scheme for the rotor-side and line-side converters using the first and second sets of switching pulses, respectively, to obtain an output voltage from the voltage source converter to a desired magnitude, shape, and/or frequency.

Abstract: A power conversion assembly includes a power converter having a plurality of switching devices, a power source electrically coupled to the power converter, and a direct current (DC) filter circuit bridging the power converter and the power source. The DC filter circuit includes a DC link having a positive rail, a negative rail, and a capacitor bank. The capacitor bank includes a first set of capacitors being a first type of capacitors and a second set of capacitors being a different, second type of capacitors. Each capacitor in the first set of capacitors is positioned closer to a respective switching device of the plurality of switching devices than a corresponding capacitor of the second set of capacitors to minimize impedance between each capacitor in the first set of capacitors and the respective switching device such that a majority of ripple current from the plurality of switching devices passes through the first set of capacitors.

Abstract: A method for controlling a three-level back-to-back voltage source power conversion assembly includes receiving an indication of a DC or AC unbalance occurring in voltage of a DC link. The power conversion assembly has a first power converter coupled to a second power converter via the DC link. In response to receiving the indication, the method includes activating a balancing algorithm that includes determining a deviation of a midpoint voltage of the DC link as a function of a total voltage of the DC link, calculating a voltage compensation needed for pulse-width modulation signals of the power conversion assembly based on the deviation, and coordinating common mode voltage injection from each of the power converters independently at a neutral point of the power conversion assembly based on the voltage compensation, thereby minimizing the at least one of the DC unbalance or the AC unbalance at any given operating condition.

Abstract: A method for controlling a voltage source power converter of a renewable energy power conversion system includes providing the voltage source power converter having, at least, a rotor-side converter and a line-side converter. The method also includes generating, via a converter controller, a first set of switching pulses based on a third-harmonic phase opposition carrier-based pulse width modulation (PO_CB_PWM) scheme. Further, the method includes generating, via the converter controller, a second set of switching pulses based on a third-harmonic in phase carrier-based pulse width modulation (IP_CB_PWM) scheme. As such, the method includes implementing, via the converter controller, a pulse-width modulation scheme for the rotor-side and line-side converters using the first and second sets of switching pulses, respectively, to obtain an output voltage from the voltage source converter to a desired magnitude, shape, and/or frequency.