The present disclosure relates to power management apparatuses and systems utilizing synchronous common coupling. A power management apparatus may comprise a plurality of ports, and a plurality of electrically isolated stacks connected through a synchronous common coupling. Each electrically isolated stack may include a plurality of cascaded stages and connected to a source or load through one of the plurality of ports. The synchronous common coupling connects may only power between each of the plurality of electrically isolated stacks and is configured to maintain electrical isolation for each of the plurality of stages in the plurality of electrically isolated stacks.

A low voltage, low frequency multi-level power converter capable of power conversion is disclosed. The power converter may include a low voltage, low frequency circuit that includes a plurality of phase-shifting inverters in series; a plurality of low voltage source inputs, and a plurality of phase-shifting inverters in series. Each of the plurality of phase-shifting inverters may be configured to receive at least one of the plurality of low voltage source inputs; and generate at least one square wave output. A semi-sine wave output may be derived from the generated at least one square wave output.

A low voltage, low frequency multi-level power converter capable of power conversion is disclosed. The power converter may include a low voltage, low frequency circuit that includes a plurality of phase-shifting inverters in series; a plurality of low voltage source inputs, and a plurality of phase-shifting inverters in series. Each of the plurality of phase-shifting inverters may be configured to receive at least one of the plurality of low voltage source inputs; and generate at least one square wave output. A semi-sine wave output may be derived from the generated at least one square wave output.

A battery module comprising a plurality of battery cell units, each one comprising: a battery cell having a first pole and a second pole, and a switch circuit, comprising a plurality of switches, and a switch controller arranged to control the switches of the switch circuit to enter either of a first state, in which the battery cell is connected in parallel with a neighboring battery cell, and a second state, in which the battery cell is connected in series with a neighboring battery cell. The battery module is configured to control the switching between the first and second states on a probabilistic basis.

A power converter includes two arms for each phase between DC terminals, and each arm is formed by connecting a plurality of converter cells in series. A control device includes an arm voltage command generation unit which generates, for each arm, an arm voltage command for the plurality of converter cells. The arm voltage command is generated by superimposing a zero-phase-sequence voltage command having a frequency component that is three times an AC fundamental frequency. Phase adjustment of the zero-phase-sequence voltage command is performed on the basis of voltage of a DC capacitor in the converter cell and the arm voltage command.

A power converter includes two arms for each phase between DC terminals, and each arm is formed by connecting a plurality of converter cells in series. A control device includes an arm voltage command generation unit which generates, for each arm, an arm voltage command for the plurality of converter cells. The arm voltage command is generated by superimposing a zero-phase-sequence voltage command having a frequency component that is three times an AC fundamental frequency. Phase adjustment of the zero-phase-sequence voltage command is performed on the basis of voltage of a DC capacitor in the converter cell and the arm voltage command.

The present disclosure discloses a flow battery system and a large-scale flow battery energy storage device. The flow battery system comprises multiple flow batteries; each of the flow batteries comprises a battery pack A, a battery pack B, a battery pack C, and a set of electrolyte circulation system used by the battery pack A, the battery pack B and the battery pack C; the battery pack A, the battery pack B and the battery pack C comprised in each flow battery are independent of each other in the circuit. According to the present disclosure, at least two sets of electrolyte circulation system are saved under the same power scale, such that the system stability is improved while the cost is reduced.

A power conversion device according to an embodiment includes a cell, a first sensor, a second sensor, a storage, a first controller, and a second controller. The first controller is configured to control or protect the cell on the basis of at least one of an output result of the first sensor and an output result of the second sensor. The second controller, in a case in which a change in at least one of the output result of the first sensor and the output result of the second sensor satisfies a first condition, is configured to execute at least one of a first operation of storing the output result of the first sensor in the storage, a second operation of storing the output result of the first sensor in the storage over a second period longer than a first period, and a third operation of storing the output result of the second sensor instead of the output result of the first sensor.

The invention relates to a method of controlling the on-time of a plurality of energy modules of an energy storage. The energy storage comprising a plurality of series connected energy modules forming an energy module string. A string controller is controlling which of the individual energy modules that is part of a current path through the energy module string, by control of the status of a plurality of switches. The string controller is controlling the frequency of the energy module string voltage according to an electric system reference related to a system to which the energy storage is connected. And wherein the string controller is controlling the switches of the individual energy modules so that each of the individual energy modules that are required to be included in the current path to establish the energy modules string voltage are included in the current path for at least a minimum on-time.

A multi-level inverter topology is disclosed. A power converter circuit converts a DC source at its input to provide an alternating current (AC) at its output. The power converter circuit may have a controller operably attached to multiple series connections of switches. The controller may control one or more of the multiple series connections of switches to convert a DC input to provide multi-level AC voltages with DC offset across two terminals of the power converter circuit. The multi-level AC voltages with DC offset may then be converted by use of a plurality of series connections of switches to provide a single-phase AC voltage at a first output terminal with respect to at least one of a neutral potential, an earth potential, or a terminal of the power converter circuit.