A converter control arrangement (18) for regulating the output current of a dc source power converter (16) comprises a current regulator (20) for regulating the output current based on a comparison of an output current value (I.sub.out) of the dc source power converter (16) with a desired target current value (I.sub.tgt). When the output voltage value (V.sub.out) of the dc source power converter (16) is within a normal operating voltage range between minimum and maximum voltage values (V.sub.min, V.sub.max) defined with respect to a voltage reference value (V.sub.ref) of the dc source power converter (16), the converter control arrangement (18) controls the target current value (I.sub.tgt) so that it is equal to a desired reference current value (I.sub.ref). When the output voltage value (V.sub.out) is outside the normal operating voltage range, which typically indicates a fault condition, the converter control arrangement (18) modulates the reference current value (I.sub.ref) to provide a target current value (I.sub.tgt) that is less than the reference current value (I.sub.ref).

A split drive transformer (SDT) and use of such a transformer in a power converter is described. The power converter includes a power and distributor circuit configured to receive one or more input signals and provides multiple signals to a first side of the SDT. The SDT receives the signals provided to the first side thereof and provides signals at a second side thereof to a power combiner and rectifier circuit which is configured to provide output signals to a load. In some embodiments, the SDT may be provided as a switched-capacitor (SC) SDT. In some embodiments, the power converter may optionally include a level selection circuit (LSC) on one or both of the distributor and combiner sides.

A split drive transformer (SDT) and use of such a transformer in a power converter is described. The power converter includes a power and distributor circuit configured to receive one or more input signals and provides multiple signals to a first side of the SDT. The SDT receives the signals provided to the first side thereof and provides signals at a second side thereof to a power combiner and rectifier circuit which is configured to provide output signals to a load. In some embodiments, the SDT may be provided as a switched-capacitor (SC) SDT. In some embodiments, the power converter may optionally include a level selection circuit (LSC) on one or both of the distributor and combiner sides.

The present DC power supply and distribution system comprises: a plurality of power distribution lines each connected to a respective one of a plurality of loads; a first converter to receive an AC voltage from a commercial AC power source, convert the received AC voltage into a plurality of DC voltages and supply each of the plurality of DC voltages to a respective one of the plurality of power distribution lines; a second converter to receive a DC power from a power generating and/or storing source, convert the received DC power into a plurality of DC powers, and supply each of the plurality of DC powers to a respective one of the plurality of power distribution lines; and a controller to enhance the second converter in efficiency by controlling the first converter so that a ratio of the plurality of DC voltages is a predetermined first ratio.

The present DC power supply and distribution system comprises: a plurality of power distribution lines each connected to a respective one of a plurality of loads; a first converter to receive an AC voltage from a commercial AC power source, convert the received AC voltage into a plurality of DC voltages and supply each of the plurality of DC voltages to a respective one of the plurality of power distribution lines; a second converter to receive a DC power from a power generating and/or storing source, convert the received DC power into a plurality of DC powers, and supply each of the plurality of DC powers to a respective one of the plurality of power distribution lines; and a controller to enhance the second converter in efficiency by controlling the first converter so that a ratio of the plurality of DC voltages is a predetermined first ratio.

A cathodic protection system providing substantially complete coverage to individual steel-in-concrete units in a multi-unit structure. The system includes a power supply, an electronic circuit board, a header cable, anode wire in each unit connected to the header cable, an adhesive fiber mat in each unit, and a conductive coating in each unit.

A cathodic protection system providing substantially complete coverage to individual steel-in-concrete units in a multi-unit structure. The system includes a power supply, an electronic circuit board, a header cable, anode wire in each unit connected to the header cable, an adhesive fiber mat in each unit, and a conductive coating in each unit.

In a multilevel converter, three first rectifying elements are respectively connected between three arms and a negative voltage terminal. Three second rectifying elements are respectively connected to the three first rectifying elements in antiparallel. During a normal operation, current flows in the three first rectifying elements and the three second rectifying elements. When a short circuit accident occurs between two DC power transmission lines, the three first rectifying elements are brought into the non-conductive state, thereby interrupting and quickly attenuating inter-arm direct current flowing in four arms and the like.

A power converting device, in one possible configuration, includes a chopper circuit with a first semiconductor switching device, a fast recovery diode, and an inductor of which one end is connected to a connection point connecting between the first semiconductor switching device and fast recovery diode; a series circuit, connected in parallel with the fast recovery diode, including a rectifying diode with a greater reverse recovery loss and a smaller forward voltage drop than those of the fast recovery diode, and a second semiconductor switching device. The second semiconductor switching device has a lower breakdown voltage and a smaller forward voltage drop than those of the first semiconductor switching device, is configured to turn on when the first semiconductor switching device is turned off, and is configured to turn off at a timing before the first semiconductor switching device shifts from an off-state to an on-state.

Precharging systems and methods are presented for precharging a DC bus circuit in a power conversion system, in which precharging current is connected through a precharging resistance coupled between only a single AC input line and the DC bus circuit when the DC bus voltage is less than a non-zero threshold, and a controller individually activates controllable rectifier switching devices when the DC bus voltages greater than or equal to the threshold using DC gating or pulse width modulation to selectively provide a bypass path around the precharging resistance for normal load currents in the power conversion system.