An electrical power distribution system includes a first high side sub-module including a high side converter and a high side energy storage device. The first high side sub-module is electrically coupled to a high side load that requires a high voltage or medium voltage DC, the high voltage DC being higher than the medium voltage DC. The system also includes a first low side sub-module including a low side converter and a low side energy storage device. The first high side sub-module and the first low side sub-module are configured to be inductively coupled. The first high side sub-module and the first low side sub-module form a first module.

There is described a power supply unit having at least one alternating current (AC) input and at least one direct current (DC) output for producing an output voltage. The power supply unit comprises at least one input transformer coupled to the at least one AC input and at least one rectification circuit defining an AC side and a DC side, and coupled to the at least one input transformer on the AC side. The at least one rectification circuit comprises a diode rectifier section on the AC side comprising at least one set of diode rectifiers, and a controlled rectifier section in series with the diode rectifier section and configured for producing a variable load voltage to modulate the output voltage between a base voltage and a maximum value of the output voltage using at least one set of three single-phase controlled rectifiers usable as one to three DC outputs to form a three-phase controlled rectifier.

Disclosed is an optimized energy interconnection system for an urban railway train in the technical field of urban railway transportation power supply, for addressing the technical problem that distribution of regenerative braking energy flows cannot be accurately determined. The system includes a DC intermediate bus and a multi-port flow controllable energy router. The multi-port flow controllable energy router can comprehensively control a source and a load connected in parallel on the DC intermediate bus and thus can accurately determine the distribution of regenerative braking energy flows, thereby forming a well-developed system for evaluating usage of the braking energy.

A power supply device includes: “m×n” switching elements; capacitors connected in series to corresponding ones of the switching elements and forming “m×n” series circuits; a charger charging the capacitors; “m” transformers in which primary windings are connected to both ends of corresponding ones of “m” parallel circuits formed by connecting “n” units of the series circuits in parallel to one another with the polarity aligned; a current detection unit detecting, as a detected current value, current flowing through a multistage series circuit in which secondary windings of the transformers are sequentially connected in series so that both ends of the circuit serve as output terminals; a control unit outputting a command signal generated based on the detected current value and a current command being a target value of the current output from the output terminals; and a drive unit driving the switching elements and the charger based on the command signal.

Aspects of the invention overcome a monolithic approach to conventional low-frequency LPTs by using a high-frequency solid-state alternating current ac/ac modular power-conversion approach. Embodiments of the invention enable the ability to incorporate new technologies without in all cases redoing a LPT design from scratch. Furthermore, given that LPTs are for the long term, aspects of the invention ensure that they are durable, efficient, and fault tolerant with overloading capability.

A conversion device includes: an inductor electrically connected to the AC power grid; a first-stage converter configured to output a bus voltage according to the AC power grid, wherein the first-stage converter includes an N-level alternating current-direct current (AC-DC) converter, and the N-level AC-DC converter includes a plurality of switch bridge arms, wherein both an upper bridge arm and a lower bridge arm of each of the plurality of switch bridge arms of the N-level AC-DC converter include a plurality of semiconductor devices connected in series, and a rated withstand voltage Vsemi of each of the semiconductor devices is greater than or equal to (Vbus*δ)/((N−1)*Nseries*λ); and a second-stage converter configured to convert the bus voltage into an output voltage to supply energy to the load.

In one embodiment, an apparatus includes a surge voltage blocker circuit to couple between a distribution grid network and a grid-side power converter of a power conversion system. The surge voltage blocker circuit may include a plurality of series-coupled AC switch circuits, each including: a bidirectional switch formed of a first power transistor and a second power transistor; and a transient voltage suppression device coupled in parallel with the bidirectional switch.

This application discloses a photovoltaic power generation system and method, and the system includes an inverter and at least one shutdown apparatus. A type of the shutdown apparatus includes at least one of a shutdown device and an optimizer; and an input end of each shutdown apparatus is connected to a corresponding PV module, and power of the corresponding PV module is output. In the system, when a parameter of the inverter meets a preset condition, some shutdown apparatuses are turned off to lower an input voltage of the inverter, and ensure that an input end of the inverter has a direct current source, and the system can operate as usual; and the preset condition is that the input voltage of the inverter is greater than a first preset voltage, or an input current of the inverter is less than a first preset current.

A first capacitor and a second capacitor are connected in series through a neutral point on the DC side of an inverter. A first converter receives an input voltage from a power source and outputs a first DC voltage to the first capacitor. A second converter receives a common input voltage and outputs a second DC voltage to the second capacitor. A control circuit controls the first converter such that the first DC voltage is controlled in accordance with a preset first voltage command value and controls the second converter such that the second DC voltage is controlled in accordance with a second voltage command value set equivalent to the first voltage command value.

Provided is a power conversion system that can suppress a fault in a short-circuiting switch that bypasses a fault unit and enhance the reliability and redundancy of the system. The power conversion system is provided with a plurality of power converter units that are formed by using semiconductor switch elements and are connected in series, and comprises: switch elements that are provided to input terminals and/or output terminals of the power converter units and bypass the power converter units; and overvoltage suppressing elements which are connected in parallel with the switch elements and in which conducting states are changed by an application of a prescribed voltage.