Abstract: A high voltage direct current (HVDC) converter system includes a line commutated converter (LCC) configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in only one direction. The HVDC converter system also includes a buck converter configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in one of two directions. The LCC and the buck converter are coupled in parallel to an AC conduit and are coupled in series to a DC conduit. The HVDC converter system further includes a filtering device coupled in parallel to the buck converter through the AC conduit. The filtering device is configured to inject AC current having at least one harmonic frequency into the AC conduit.

Abstract: A high voltage direct current (HVDC) converter system includes at least one line commutated converter (LCC) and at least one current controlled converter (CCC). The at least one LCC and the at least one CCC are coupled in parallel to at least one alternating current (AC) conduit and are coupled in series to at least one direct current (DC) conduit. The at least one LCC is configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in only one direction. The at least one current controlled converter (CCC) is configured to convert a plurality of AC voltages and currents to a regulated DC voltage of one of positive and negative polarity and a DC current transmitted in one of two directions.

Abstract: An electronics power system includes a plurality of substantially identical power electronic modules. Each power electronic module includes a single-phase DC/AC inverter having an output side. Each power electronic module further includes a medium/high-frequency-isolated DC/DC current-to-voltage converter having an input side. The medium/high-frequency-isolated DC/DC current-to-voltage converter drives the single-phase DC/AC inverter. Each DC/DC converter and its corresponding DC/AC inverter are connected back-to-back sharing a common DC-link. The plurality of power electronics modules is stacked together in series at the input side and in parallel or series/parallel at the output side.

Abstract: A high voltage, high power multi-level drive structure includes a plurality of neutral-point-piloted (NPP) converter cells stacked together. At least one clamping diode is connected to one or many NPP converter cell to provide a neutral-point-pilot-clamped (NPPC) converter structure. Flying capacitors connected to the NPPC converter structure yield a neutral-point-clamped-flying-capacitor converter cell structure.

Abstract: A load bypass switch enables continuous power to remote loads in the event of 1) failure of one or more remote loads, or 2) faults within the remote loads, within a dc power system. The bypass switch utilizes the passive components of the dc loads or inverters and therefore reduces overall component count. A black start method for the remote dc system uses the same passives present inside the loads/inverters and simultaneously uses some of the features of the bypass switch. A bypass-module-yard uses multiple bypass switches enabling continuous power to the remote loads in the event of failure of one or more power distribution cables (in-feed to the remote loads) located remotely in the dc system.

Abstract: This patent document discloses power electronic transformers having a high-frequency link. An example apparatus include a transformer having a primary winding and a secondary winding, the transformer is configured to receive a primary power signal having a first frequency, a primary converter configured to selectively oscillate polarity of the primary windings with respect to the secondary windings at a second frequency, the second frequency substantially substantially higher than the first frequency, a secondary converter coupled to the secondary winding, the secondary converter configured to provide a load power signal using a high frequency power signal generated using the secondary winding. The secondary converter can be configured to reduce current flow in the primary winding when the polarity of the primary winding is switched, the reduced current follow is configured to reduce disturbances resulting from leakage inductance of the transformer.

Abstract: This patent document discloses power electronic transformers having a high-frequency link. An example apparatus include a transformer having a primary winding and a secondary winding, the transformer is configured to receive a primary power signal having a first frequency, a primary converter configured to selectively oscillate polarity of the primary windings with respect to the secondary windings at a second frequency, the second frequency substantially substantially higher than the first frequency, a secondary converter coupled to the secondary winding, the secondary converter configured to provide a load power signal using a high frequency power signal generated using the secondary winding. The secondary converter can be configured to reduce current flow in the primary winding when the polarity of the primary winding is switched, the reduced current follow is configured to reduce disturbances resulting from leakage inductance of the transformer.