Units for distributing three-phase power to a plurality of chain motors are provided, as are used to raise and suspend production elements such as lighting, sound, video, and scenery. Remote switching and phase reversal of such power are also provided. In the prior art, such switching has been performed by large, heavy contactors inserted between the single power input and its distribution to plural outputs for motors, making the unit difficult to handle and ship. Provided herein are power switching and phase reversal performed by a plurality of parallel such means, reducing the current requirements for each, and thereby the size, weight, and cost of the whole. In some embodiments, the single power input is replaced by a by a cable delivering a plurality of two-phase circuits to the unit which derives the three-phase circuits necessary for chain motors therefrom.

An electric power conversion control apparatus includes: a first converter of the first electric power conversion control apparatus and a second converter of the second electric power conversion control apparatus, which feed electric power to a first winding wire and a second winding wire of a dual three-phase motor; a first controller and a second controller, which control the first converter and the second converter; a communication line, which is connected between the first controller and the second controller; and a fifth signal wire for deactivating the operation of the second converter, from the first controller. When a fault is caused by communication errors, the first controller uses the fifth signal wire to deactivate the operation of the second converter, and the electric power conversion control apparatus switches to one system operation by the first controller.

An electric power conversion control apparatus includes: a first converter of the first electric power conversion control apparatus and a second converter of the second electric power conversion control apparatus, which feed electric power to a first winding wire and a second winding wire of a dual three-phase motor; a first controller and a second controller, which control the first converter and the second converter; a communication line, which is connected between the first controller and the second controller; and a fifth signal wire for deactivating the operation of the second converter, from the first controller. When a fault is caused by communication errors, the first controller uses the fifth signal wire to deactivate the operation of the second converter, and the electric power conversion control apparatus switches to one system operation by the first controller.

A line interface filter apparatus to couple a drive or group of drives to a shared multiphase AC bus, including individual phase circuits having an inductor coupled between a respective bus and drive phase lines, a tapped resistor coupled to the respective drive phase line, and a capacitor coupled between the resistor and a common connection of the capacitors of the individual phase circuits, where the capacitance of the capacitors is 5 to 15 times a per-phase equivalent capacitance of the drive or group of drives, and the resistance of the resistors is two times a damping ratio times a square root of a ratio of the filter inductance to the filter capacitance, where the damping ratio ζ is greater than or equal to 1.0 and less than or equal to 2.0.

A method and apparatus include a primary transformer coil, a secondary transformer coil, and a center tapped inductor coupled to the secondary transformer coil. A first switch may be in electrical communication with the center tapped inductor and may be configured to affect the first output voltage. A second switch may be in electrical communication with the center tapped inductor and may be configured to affect the second output voltage. In a particular example with an analog current (AC) output voltage, the two output voltages are out of phase to each other. In a direct current (DC) implementation, the transformer may be operated to output a positive and a negative output voltage. The apparatus may function as a resonant converter, or may operate in non-resonant mode. In one implementation, an H bridge may provide reactive power support. An inductor filter may be in electrical communication with the secondary transformer coil. Where desired, a diode bridge may be in electrical communication with the primary transformer coil.

A method and apparatus include a primary transformer coil, a secondary transformer coil, and a center tapped inductor coupled to the secondary transformer coil. A first switch may be in electrical communication with the center tapped inductor and may be configured to affect the first output voltage. A second switch may be in electrical communication with the center tapped inductor and may be configured to affect the second output voltage. In a particular example with an analog current (AC) output voltage, the two output voltages are out of phase to each other. In a direct current (DC) implementation, the transformer may be operated to output a positive and a negative output voltage. The apparatus may function as a resonant converter, or may operate in non-resonant mode. In one implementation, an H bridge may provide reactive power support. An inductor filter may be in electrical communication with the secondary transformer coil. Where desired, a diode bridge may be in electrical communication with the primary transformer coil.

An auto-transformer rectifier system comprising an 18-pulse (or multiple of 18-pulse) autotransformer rectifier unit ATRU having three, or a multiple of three, diode bridge rectifiers and a balancing resistor to balance the power flow through the diode bridge rectifiers, wherein the balancing resistor has a variable resistance, and further comprising a controller configured to identify imbalances between power flows of the respective diode bridge rectifiers and to adjust the resistance of the balancing resistor in response to the detected imbalance.

A solid-state transformer (10) that maintains output voltage continuity during maintenance is provided. The solid-state transformer includes an input end (101), a plurality of power units (U1 to UM), and an output end (102). The input end is configured to input first three-phase alternating-current electrical power. The plurality of power units are connected in parallel to the input end and the output end, and each power unit is configured to convert the first three-phase alternating-current electrical power into first direct-current electrical power, and output the first direct-current electrical power from the output end. A power supply system (100) including the foregoing solid-state transformer is further included.

A solid-state transformer (10) that maintains output voltage continuity during maintenance is provided. The solid-state transformer includes an input end (101), a plurality of power units (U1 to UM), and an output end (102). The input end is configured to input first three-phase alternating-current electrical power. The plurality of power units are connected in parallel to the input end and the output end, and each power unit is configured to convert the first three-phase alternating-current electrical power into first direct-current electrical power, and output the first direct-current electrical power from the output end. A power supply system (100) including the foregoing solid-state transformer is further included.

An autotransformer for converting three-phase AC power to nine-phase AC power. The autotransformer includes three coils each having serial connected windings and non-serial connected windings. The combination of the serial and non-serial windings are interconnected to form a polygon for a total of six windings per phase, in an arrangement which reduces the power rating of an autotransformer suitable for 18-pulse AC to DC power converters. There are a plurality of direct outputs that are equal in magnitude and are out of phase with respect to the voltages at the input. The input is offset from the nine outputs to create the required phase magnitudes for DC power converters.