A power distribution system includes at least two DC buses and at least two AC buses and a plurality of converter units interconnecting the DC buses and the AC buses in a ring. The system may further include one or more AC power sources (e.g., utility feeds, engine-generator sets, etc) connected to selected ones of the AC buses and/or one or more DC power sources (batteries, capacitor banks, fuel cells, etc.) connected to selected ones of the DC buses. The ring configuration can support a variety of AC and DC loads and provide redundancy and power distribution among the power sources.

A power distribution system includes at least two DC buses and at least two AC buses and a plurality of converter units interconnecting the DC buses and the AC buses in a ring. The system may further include one or more AC power sources (e.g., utility feeds, engine-generator sets, etc) connected to selected ones of the AC buses and/or one or more DC power sources (batteries, capacitor banks, fuel cells, etc.) connected to selected ones of the DC buses. The ring configuration can support a variety of AC and DC loads and provide redundancy and power distribution among the power sources.

The present patent application relates to a method and equipment for eliminating harmonics based on two complementary techniques, namely the elimination of harmonics by selective harmonic elimination pulse-width modulation in conjunction with the multiple-wiring transformer. The association of these two resources is capable of reducing the harmonic distortion of currents to extremely low values, providing a truly unitary power factor. The technology is suitable for low and medium intensity alternating current—direct current and direct current—alternating current converters, which make interface with the electricity network and should have low harmonic distortion of the current because of the high power value involved, and also because of fragility of the electricity network (low power of short circuit at the coupling point).

A method and an electronic device for power allocation of multi-parallel power electronic transformers, the method including: determining a quantity of conversion stages of the power electronic transformers; obtaining a load ratio-efficiency relationship between the two ports of each conversion stage in turn, performing a curve fitting to obtain a load ratio-efficiency curve of each conversion stage of the power electronic transformers; calculating a load ratio-loss relationship of each conversion stage, based on the load ratio-efficiency curve of each conversion stage; obtaining a multi-parallel minimum-operation-loss power allocation curve of each conversion stage; performing a piecewise curve fitting of the minimum-operation-loss power allocation curve to obtain a multi-parallel optimum power allocation mathematical model of each stage; and determining an optimum power allocation to each port of the multi-parallel power electronic transformers, based on the multi-parallel optimum power allocation mathematical model of each stage.

A capacitor based energy storage system (CBESS) and methods of using it are disclosed. The CBESS uses meta-capacitors in its capacitive energy storage devices (CESD) to configure capacitive energy storage cells (CESC), which are used to configure capacitive energy storage modules (CESM) to achieve the CBESS's function as an uninterruptible power supply. The CBESS is connected to a power generation system (PGS), a load, and a power grid. When the grid is in an abnormal state, the CESM is simultaneously charged with power from the PGS and used to supply power to the load. If a remaining amount of power of a CESM is less than a predetermined level, the CESM is charged with power from PGS or grid. The CBESS interfaces with a computer system or network to buy or sell electricity to the grid depending on grid electricity cost and CESD charging states.

A charging device according to an exemplary embodiment of the present invention may include: a battery adapted and configured to store a DC voltage, first and second motors adapted and configured to operate as a motor or a generator, first and second inverters adapted and configured to operate the first and second motors, a voltage transformer adapted and configured to boost the DC voltage of the battery to supply it to the first and second inverters and boosts the DC voltage of the inverter to supply it to the battery, and a charging controller adapted and configured to operate the first and second inverters as a booster or operate the voltage transformer as a buck booster according to a voltage that is input through a neutral point of the first and second motors and the voltage of the battery.

An electric power control system includes: a bidirectional electric power converter including AC and DC terminals, the AC terminal being connected to an AC power system, the DC terminal being connected to a DC power system to which one or more DC power loads are connected, the bidirectional electric power converter mutually converting AC power of the AC power system and DC power of the DC power system; an electric power storage that is connected to the DC power system and stores electric power of the DC power system; and a bidirectional electric power conversion controller that performs first control of controlling an output or input of the AC terminal of the bidirectional electric power converter such that a charge current, discharge current, charge electric power, or discharge electric power of the electric power storage coincides with a predetermined target current value or a predetermined target electric power value.

An electric power control system includes: a bidirectional electric power converter including AC and DC terminals, the AC terminal being connected to an AC power system, the DC terminal being connected to a DC power system to which one or more DC power loads are connected, the bidirectional electric power converter mutually converting AC power of the AC power system and DC power of the DC power system; an electric power storage that is connected to the DC power system and stores electric power of the DC power system; and a bidirectional electric power conversion controller that performs first control of controlling an output or input of the AC terminal of the bidirectional electric power converter such that a charge current, discharge current, charge electric power, or discharge electric power of the electric power storage coincides with a predetermined target current value or a predetermined target electric power value.

A power conversion device includes a power conversion circuit having first, second, third, and fourth switches, and a controller. The controller generates a first pulse signal for controlling the turning on and off of the first and fourth switches and a second pulse signal for controlling the turning on and off of the second and third switches, based on a circuit current flowing in the power conversion circuit and a voltage of an AC power source. The turning on and off of the switches causes the power conversion device to have a flowing current in which a high frequency component is mixed with a low frequency component.

A semiconductor switching string includes a plurality of series-connected semiconductor switching assemblies, each having a main semiconductor switching element that includes first and second connection terminals. The main semiconductor switching element also has an auxiliary semiconductor switching element electrically connected between the first and second connection terminals. Each semiconductor switching assembly also includes a control unit configured to switch on a respective auxiliary semiconductor switching element to selectively create an alternative current path between the first and second connection terminals whereby current is diverted to flow through the alternative current path to reduce the voltage across the corresponding main semiconductor switching element. The or each control unit is further configured to switch on the auxiliary semiconductor switching element when the voltage across the corresponding main semiconductor switching element differs from a voltage reference derived from the voltage across all of the main semiconductor switching elements.