Abstract: A hot pressing apparatus includes a positioning template having a forming region for placing a workpiece, a hot pressing template, a plurality of positioning blocks, and a lifting mechanism. A plurality of holes is formed in the forming region along a periphery of the forming region. The positioning blocks are movably disposed outside the forming region along the periphery of the forming region for positioning the workpiece in the forming region. The hot pressing template is movable between a hot pressing position and a releasing position for hot pressing the workpiece located in the forming region cooperatively with the positioning template when moving to the hot pressing position. The lifting mechanism includes a plurality of pillars movably disposed in the holes respectively and a driving device for driving each pillar to extend out from the corresponding hole so as to lift the workpiece.

Abstract: A reshaping device for reshaping a workpiece, includes a worktable, a reshaping assembly, a measuring unit, a positioning assembly, and a controller electrically connected to the reshaping assembly, the measuring unit, and the positioning assembly. The positioning assembly includes a pair of positioning subassemblies and a movable supporting subassembly. Each positioning subassembly comprises a supporting bracket and two positioning members, the two supporting brackets are distributed on the worktable, spaced from each other, for holding the workpiece. The movable supporting subassembly comprises two transmission members and two driving members. The two transmission members are stacked on top of each other and disposed on the worktable. The two driving members are respectively assembled to the two transmission members and drive the two transmission members to slide along different directions, thereby supporting the workpiece. The present disclosure further discloses a positioning assembly.

Abstract: A ground fault detection system for locating a ground fault in a direct current (DC) power transfer system is provided. The system includes a ground fault detection component and a current sensor. The ground fault detection component includes a first switch and a first resistive element electrically coupled to each other in a series configuration. The ground fault detection component also includes a second switch and a second resistive element electrically coupled to each other in a series configuration. Furthermore, the current sensor is operatively coupled to a load and is configured to measure a fault current at the load upon switching at least one of the first switch or the second switch to a conducting state.

Abstract: An over-voltage protection system includes an electronic valve connected across two terminals of a circuit and an over-voltage detection circuit connected across one of the plurality of semiconductor devices for detecting an over-voltage across the circuit. The electronic valve includes a plurality of semiconductor devices connected in series. The over-voltage detection circuit includes a voltage divider circuit connected to a break-over diode in a way to provide a representative low voltage to the break-over diode and an optocoupler configured to receive a current from the break-over diode when the representative low voltage exceeds a threshold voltage of the break-over diode indicating an over-voltage condition. The representative low voltage provided to the break-over diode represents a voltage across the one semiconductor device.

Abstract: A power system for a marine ship includes a plurality of protection zones, wherein at least two protection zones are coupled to each other via at least one bus-tie converter. Each of the protection zones includes a plurality of direct current (DC) buses and a plurality of power converters. The bus-tie converter includes at least two converter legs coupled by at least one inductor. Each converter leg includes a first branch connected with a snubber circuit by an intermediate switching device. The first branch includes two outer switching devices and at least one inner switching device connected between the two outer switching devices. The snubber circuit includes a combination of a diode, a resistor and a capacitor. A controller controls the operation of the plurality of power converters and the at least one bus-tie converter.

Abstract: A power converter includes at least one leg having a first string operatively coupled to a second string via a first connecting node and a second connecting node. The first string includes a first branch and a second branch operatively coupled via a third connecting node. Each of the branches has a plurality of switching units, a controllable semiconductor switch and the first connecting node and the second connecting node. The first string is operatively coupled across a first bus and a second bus. Furthermore, the second string includes a plurality of controllable semiconductor switches.

Abstract: A power system for a marine ship includes a plurality of protection zones, wherein at least two protection zones are coupled to each other via at least one bus-tie converter. Each of the protection zones includes a plurality of direct current (DC) buses and a plurality of power converters. The bus-tie converter includes at least two converter legs coupled by at least one inductor. Each converter leg includes a first branch connected with a snubber circuit. The first branch includes two outer switching devices and at least one inner switching device connected between the two outer switching devices. The first branch also includes a damping resistor coupled between the two outer switching devices to dissipate a fault current. The snubber circuit includes a combination of a diode, a resistor and a capacitor. A controller controls the operation of the plurality of power converters and the at least one bus-tie converter.

Abstract: A power converter including one or more converter legs is provided. Each converter leg includes a first string including a plurality of switches coupled to each other in series. The one or more converter legs also include a second string operatively coupled to the first string at a first node and a second node in a parallel configuration, where the second string includes a plurality of switching units, and where a second string of one converter leg of the one or more converter legs is operatively coupled to second strings corresponding to other converter legs in the one or more converter legs.

Abstract: A power system for a marine ship includes a plurality of protection zones, wherein at least two protection zones are coupled to each other via at least one bus-tie converter. Each of the protection zones includes a plurality of direct current (DC) buses; wherein DC buses which do not have same DC voltage are coupled to each other via at least one DC to DC converter. Furthermore, at least one energy source is coupled to at least one DC bus via a power electronic converter.

Abstract: A system and method support a supply chain management platform for a supply chain management environment. The supply chain management platform can provide a graphical representation of one or more material inventory trends in the supply chain management environment. Additionally, the supply chain management platform can using one or more tokens to display one or more activities on the graphical representation of the one or more material inventory trends, wherein the one or more activities contribute to inventory change in the supply chain management environment. Furthermore, the supply chain management platform allows a user to perform one or more supply chain scheduling operations in the supply chain management environment based on the graphical representation.

Abstract: Power systems and methods are disclosed herein. The systems and methods use a switching system coupled with a power source and subterranean pumps for pumping a resource from beneath a surface of earth. A first capacitor is between a first switching device and a first transformer, and stores electric energy received from the first transformer to activate the first switching device. A bias capacitor is between the first capacitor and the first switching device, and receives a bias voltage via a second transformer. The bias capacitor applies the bias voltage to the first switching device to prevent the first switching device from activating unless a combination of the voltage received by the first switching device via the first transformer and the bias voltage is at least as large as the activation voltage of the first switching device.

Abstract: A high-voltage DC (HVDC) power system and a method of controlling and protecting the HVDC power system includes a plurality of sending-end (SE) modules coupled in electrical series and a plurality of receiving-end (RE) power converter modules electrically coupled to said plurality of SE modules, the RE modules coupled in a switchyard configuration, the switchyard configuration including a plurality of load branches coupled together in electrical series, each load branch including a branch bypass switch configured to bypass load current around an associated load branch, and a branch protection system.

Abstract: DC link capacitance in a bi-directional AC/DC power converter using a full-bridge or H-bridge switching circuit can be greatly reduced and the power density of the power converter correspondingly increased by inclusion of a bi-directional synchronous rectifier (SR) DC/DC converter as a second stage of the power converter and controlling the second stage with a control loop having a transfer function common to both buck and boost modes of operation of the bi-directional SR DC/DC converter and a resonant transfer function to increase gain at the ripple voltage frequency (twice the AC line frequency) to control the duty cycle of the switches of the bi-directional SR DC/DC stage and controlling the duty cycle of the switches of the full-bridge or H-bridge switching circuit using a control loop including a notch filter at the ripple voltage frequency.

Abstract: Leakage current through stray or parasitic capacitance (which is particularly large in devices such as photovoltaic cell arrays and which are damaged by such leakage currents) due to common mode switching noise in a full bridge single phase power converter is reduced at high frequencies by magnetically coupling the two phase legs on the AC side of the power converter and connecting mid points of the AC and DC sides of the power converter and is reduced at low frequencies by use of a feedback arrangement that modifies sinusoidal modulation of the switches of the full bridge converter to function as an active filter. The magnetic coupling for the two phase legs is designed in a simple manner to avoid saturation based on volt-second considerations.

Abstract: A system for transmitting direct current (DC) power includes a system DC link for carrying power from a source to a plurality of loads and alternating current (AC) to DC power converter modules coupled in series to the system DC link on a supply side of the system DC link.

Abstract: A high-voltage DC (HVDC) power system and a method of controlling and protecting the HVDC power system includes a plurality of sending-end (SE) modules coupled in electrical series and a plurality of receiving-end (RE) power converter modules electrically coupled to said plurality of SE modules, the RE modules coupled in a switchyard configuration, the switchyard configuration including a plurality of load branches coupled together in electrical series, each load branch including a branch bypass switch configured to bypass load current around an associated load branch, and a branch protection system.

Abstract: A small signal feedback loop or feed-forward loop having gain provides substantially unconditional instability in a phase locked loop when a reference phase signal is lost. The small signal feedback or feed-forward also modifies phase locked loop bandwidth when the reference phase signal is lost to increase rapidity of response to loss of reference phase signal while maintaining insensitivity to reference voltage amplitude change while the reference phase signal is present. The performance thus achieved is particularly suitable for rapid condition detection response and control of a grid connected power converter under islanding conditions.

Abstract: A method and a high-voltage DC (HVDC) power system are provided. The system includes a plurality of sending-end (SE) modules coupled in electrical series and divided into at least two groups that each operate independently with respect to an electrical ground and a plurality of receiving-end (RE) power converter modules electrically coupled to the plurality of SE modules, the plurality of RE power converter modules including a fast ground-fault detection and control device, the plurality of RE power converter modules including a receiving-end front-end DC-DC converter controller, and an output current damping control.

Abstract: A small signal feedback loop or feed-forward loop having gain provides substantially unconditional instability in a phase locked loop when a reference phase signal is lost. The small signal feedback or feed-forward also modifies phase locked loop bandwidth when the reference phase signal is lost to increase rapidity of response to loss of reference phase signal while maintaining insensitivity to reference voltage amplitude change while the reference phase signal is present. The performance thus achieved is particularly suitable for rapid condition detection response and control of a grid connected power converter under islanding conditions.

Abstract: A hot pressing apparatus includes a positioning template having a forming region for placing a workpiece, a hot pressing template, a plurality of positioning blocks, and a lifting mechanism. A plurality of holes is formed in the forming region along a periphery of the forming region. The positioning blocks are movably disposed outside the forming region along the periphery of the forming region for positioning the workpiece in the forming region. The hot pressing template is movable between a hot pressing position and a releasing position for hot pressing the workpiece located in the forming region cooperatively with the positioning template when moving to the hot pressing position. The lifting mechanism includes a plurality of pillars movably disposed in the holes respectively and a driving device for driving each pillar to extend out from the corresponding hole so as to lift the workpiece.