A normal workflow including a plurality of steps may be defined by exemplary systems and methods for use in preparing a treatment, performing a treatment, and performing post-treatment processes. A user may be guided by one or more workflow affordances to indicate where and how to use a graphical user interface to follow the normal workflow. When a user deviates from the normal workflow, one or more deviation workflow affordances may be displayed on the graphical user interface to guide a user back to the normal workflow.

In a power conversion device in a configuration in which a plurality of power converter cells has serially connected outputs and includes a converter and an inverter as components, when a load is light, the cells also operate with a light load, and efficiency is reduced. A power conversion device has a plurality of power converter cells. The outputs of the cells are connected in series. The device has a controller that controls the cells. The cells each have a converter that converts an externally inputted power supply voltage and generates a DC link voltage and an inverter that converts the DC link voltage into an alternating current voltage and outputs the current. The controller stops a converter in some of the cells depending on power supply electric power or load electric power. The inverter continues to operate using a link capacitor as a power supply.

A power transmission network includes an AC electrical system, an AC transmission link from the AC electrical system to AC-DC converter(s), and a control system. AC-DC converter(s) include an AC connecting point connected to the AC transmission link and a DC connecting point for connection to a DC transmission link. The control system operates each AC-DC converter in an AC voltage control mode as an AC slack bus to control a magnitude and/or a frequency of an AC voltage of the AC transmission link at a steady-state value and facilitating a power transfer between its connecting points to accommodate power generated or supplied to the AC electrical system. The control system further operates each AC-DC converter in a protection mode to protect each AC-DC converter from an overvoltage and/or an overcurrent.

An objective of the invention is to provide a bidirectional power valve for current occurring in a high voltage DC conductor, control method therefor, hybrid multi-terminal HVDC System using the same. The bidirectional power valve includes a first power diode arrangement of a first conducting direction, a second power diode arrangement of a second conducting direction; a mechanical disconnector, being connected with the second power diode arrangement in series; wherein: the first power diode arrangement and the series-connected second power diode arrangement and the mechanical disconnector are connected in parallel; and the first conducting direction of the first power diode arrangement and the second conducting direction of the second power diode arrangement are opposite to each other. The current commutation and re-commutation can be achieved with less requirement of the timing accuracy of switching event which makes the usage of a mechanical disconnector and power diode feasible. This will then result in a significant reduction of cost and power transfer losses.

A system for generation and distribution of high voltage direct current (HVDC) within a contained power domain named POD and methods for making and using the same. The system and methods efficiently power Information Technology racks deployed to a data center environment, advantageously providing features and functions highly desirable for a specific application.

A series compensation device suitable to double-circuit lines is disclosed. The device includes one series transformer and one converter. One converter and dual-circuit transmission lines are respectively connected to three windings of one series transformer. In the solution provided in the present application, the device can be independently installed in a power transmission system to be used as a static synchronous series compensator, and can also be used as a component of a unified power flow controller, a convertible static compensator, an interline power flow controller and a unified power quality conditioner to be connected to a power transmission system device in series. The device can save the capacity of a converter, improve the application efficiency of the series compensation device, and reduce the cost and area occupation.

Some embodiments may include a multi-stage converter comprising: a branch connected between a positive busbar and a negative busbar; and a control device. The branch has two arms connected in series. The arms each comprise a series circuit including a plurality of two-pole submodules, an energy store, and a communication connection to the control device. The communication connection transmits state of charge of the energy store and a switching instruction for the respective submodule. For at least a subset of the submodules, the communication connection comprises a common communication connection with a plurality of insulation paths having an insulation capability in each case of at most 5 kV.

A device for extinction angle control of a high voltage direct current (HVDC) system, includes: a converter reactive power calculator calculating a reactive power variation amount of a converter included in the HVDC system, depending on firing angle control of the converter; an alternating current (AC) system short circuit level calculator calculating a short circuit level of an AC system by applying the reactive power variation amount to a short circuit level formula of the AC system connected to the HVDC system; an extinction angle variation value calculator calculating an extinction angle variation value of the converter, corresponding to the short circuit level; and an extinction angle controller controlling an extinction angle of the converter, depending on an extinction angle control value reflecting the extinction angle variation value.

A converter module for a multi-stage converter includes an energy storage device connected in parallel with a series circuit of a first and a second semiconductor switching unit. At least one of the semiconductor switching units has a bidirectional switch. A switch-on unit is connected in parallel with the bidirectional switch. With the switch-on unit there can be produced a switch-on voltage for switching on the bidirectional switch from a voltage dropping across the bidirectional switch. There is also disclosed a multi-stage converter having the novel converter module and a method for operating the converter module.

Disclosed is a phase-shifted square wave modulation technique for single-phase and three-phase IM2DC applications in HVDC/MVDC systems. A square wave based modulation waveform is applied to each cell of IM2DC and compared to the phase-shifted carrier waveforms to generate device gate signals. As a result, a higher equivalent switching frequency can be achieved, and square wave based arm and AC link waveforms will be generated. In addition, power flow of IM2DC can be controlled by a phase shift angle of the square modulation waveforms between HVS and LVS. The converter cell capacitors can be reduced in size because they are only required to smooth high switching frequency ripple components. In addition, lower TDR can be achieved due to the higher power transferring capability of square waves.