A power conversion device includes power conversion circuitry including a plurality of submodules connected in series to each other. The power conversion device further includes: a signal reception unit configured to receive a signal representing a voltage of a capacitor in each of the submodules; a time calculation unit configured to calculate at least one of a charging time of the capacitor and a discharging time of the capacitor based on the signal; and a determination unit configured to determine whether the capacitor has degraded or not based on at least one of a first result of comparison of the charging time with a reference charging time serving as a reference for determining degradation of the capacitor, and a second result of comparison of the discharging time with a reference discharging time serving as a reference for determining degradation of the capacitor.

Provided is a power distribution system that includes a reconfigurable DC/DC power converter configured to be connected with an energy storage device at an input end for receiving an input voltage therefrom, and a power electronics building block having a primary bridge unit, a secondary bridge unit magnetically connected with the primary bridge unit, and an outer bridge unit at an output end and connected to an output of the secondary bridge unit, configured to output an output voltage.

An energy storage apparatus includes: a battery system including at least one battery; a power converting unit converting input/output power characteristics of the battery system into alternating current (AC)-direct current (DC) or DC-AC; a conversion control unit controlling an operation of the power converting unit; an initial driving unit converting DC power of the battery system into AC power and supplying the AC power as power for activating the conversion control unit; and a power selecting unit detecting an output voltage of the power converting unit, selecting, based on a level of the output voltage of the power converting unit, any one of AC power output by the initial driving unit and AC power output by the power converting unit, and supplying the selected AC power as operation power of the conversion control unit.

Provided is a system for seamless power conversion in DC power distribution, the system including power conversion devices connected in parallel, and performing conversion from a AC voltage to a DC voltage between an AC power distribution network and a DC power distribution network, wherein a master power conversion device among the power conversion devices converts the AC voltage supplied from the AC power distribution network into the DC voltage including an AC voltage at a preset level, and supplies the DC voltage to a DC power distribution line of the DC power distribution network, and the remaining power conversion devices that are slave power conversion devices detect the DC voltage at the DC power distribution line in real time, and when the AC voltage is not sensed from the detected DC voltage, one of the slave power conversion devices is converted into a master power conversion device.

A power apparatus applied in an SST structure includes a first AC-to-DC conversion unit, a first DC bus, an isolated transformer, a DC-to-AC conversion unit, a second AC-to-DC conversion unit, and a second DC bus. The first AC-to-DC conversion unit has a first three-level bridge arm and a second three-level bridge arm. The first DC bus provides a first DC voltage. The isolated transformer has a primary side and a secondary side. The DC-to-AC conversion unit has a third three-level bridge arm and a fourth three-level bridge arm. The second AC-to-DC conversion unit has a fifth three-level bridge arm and a sixth three-level bridge arm. The second DC bus provides a second DC voltage.

A power apparatus applied in an SST structure includes a first AC-to-DC conversion unit, a first DC bus, an isolated transformer, a DC-to-AC conversion unit, a second AC-to-DC conversion unit, and a second DC bus. The first AC-to-DC conversion unit has a first three-level bridge arm and a second three-level bridge arm. The first DC bus provides a first DC voltage. The isolated transformer has a primary side and a secondary side. The DC-to-AC conversion unit has a third three-level bridge arm and a fourth three-level bridge arm. The second AC-to-DC conversion unit has a fifth three-level bridge arm and a sixth three-level bridge arm. The second DC bus provides a second DC voltage.

The invention relates to a conversion system (100) with a DC side and an AC side, and to an associated control method. The system (100) comprises a primary conversion block (1), a secondary conversion block (2) and a transformer block (3) with at least one primary winding (3.1) connected to the primary conversion block (1) and a secondary winding (3.2R, 3.2S, 3.2T) for each phase (R, S, T) which are connected to the secondary conversion block (2). Each conversion block (1, 2) comprises a plurality of controllable switches, and the system (100) comprises a controller (4) communicated with said switches and configured for causing the opening and closing of said switches in a controlled and coordinated manner.

Transformer assembly including a first transformer stage having a plurality of first-stage transformer cells; and a second transformer stage. An input of the second transformer stage is connected to an output of the first transformer stage. A lightning impulse breakdown voltage of a transformer cell of the second stage is at least double of a lightning impulse breakdown voltage of transformer cells of the first stage.

A power apparatus applied in an SST structure includes a first AC-to-DC conversion unit, a first DC bus, an isolated transformer, a DC-to-AC conversion unit, a second AC-to-DC conversion unit, and a second DC bus. The first AC-to-DC conversion unit has a first three-level bridge arm and a second three-level bridge arm. The first DC bus provides a first DC voltage. The isolated transformer has a primary side and a secondary side. The DC-to-AC conversion unit has a third three-level bridge arm and a fourth three-level bridge arm. The second AC-to-DC conversion unit has a fifth three-level bridge arm and a sixth three-level bridge arm. The second DC bus provides a second DC voltage.

A wireless power transfer system can be achieved at a low cost, can be used as both a power transmission apparatus and a power reception apparatus, and can cope with a change in coupling coefficient of a resonant coil of the power transmission apparatus and a resonant coil of the power reception apparatus. The wireless power transfer system is a power transmission apparatus that is able to perform bidirectional wireless power transmission, and includes the following: a power supply; a switching circuit that includes a plurality of switching devices; a resonator that includes a coil and a capacitor; a drive control circuit that controls an ON/OFF operation of each switching device of the switching circuit; and a detector that detects a resonance current flowing through the switching circuit. The drive control circuit controls the ON/OFF of each switching device of the switching circuit to perform a power transmission operation or a power reception operation based on a resonant current waveform detected by the detector.