A multi-level inverter having one or more banks, each bank containing a plurality of low voltage MOSFET transistors. A processor configured to switch the plurality of low voltage MOSFET transistors in each bank to switch at multiple times during each cycle.

A multi-level inverter having one or more banks, each bank containing a plurality of low voltage MOSFET transistors. A processor configured to switch the plurality of low voltage MOSFET transistors in each bank to switch at multiple times during each cycle.

A power conversion device that performs power conversion between a DC circuit and an AC circuit includes a power conversion circuit including a plurality of sub-modules, a failure detection device that detects an internal failure of the power conversion circuit, and a control device that generates an operation command controlling operation of each of the plurality of sub-modules. The control device acquires a voltage value of a capacitor included in each sub-module, calculates a deviation between a variance value indicating a variation in the voltage value of the capacitor included in the sub-module in a reference period and a reference variance value in the sub-module for each of a plurality of sub-modules, determines a failure section of an internal failure based on the deviation in each sub-module when the internal failure is detected, and outputs an operation command based on a determination result to each sub-module.

A method for switching control of a multi-level converter. The multi-level converter has a plurality of modules. A total switching state is formed from respective module switching states of the plurality of modules by the switching control. A current state of charge of all energy stores of the multi-level converter is provided continuously to the switching control. The switching control is divided into an offline part and an online part, wherein, in the offline part, a plurality of offline switching tables is calculated by way of optimizers in a continuous sequence and, for calculation of a respective offline switching table of the plurality of offline switching tables, a respective cost function is minimized according to at least one predefined offline optimization criterion for evaluating the total switching state. In the online part, an online switching table is selected from the plurality of offline switching tables in a continuous sequence.

A method for switching control of a multi-level converter. The multi-level converter has a plurality of modules. A total switching state is formed from respective module switching states of the plurality of modules by the switching control. A current state of charge of all energy stores of the multi-level converter is provided continuously to the switching control. The switching control is divided into an offline part and an online part, wherein, in the offline part, a plurality of offline switching tables is calculated by way of optimizers in a continuous sequence and, for calculation of a respective offline switching table of the plurality of offline switching tables, a respective cost function is minimized according to at least one predefined offline optimization criterion for evaluating the total switching state. In the online part, an online switching table is selected from the plurality of offline switching tables in a continuous sequence.

A power converter includes a plurality of switches coupled between an input bus and an output bus, a full bridge coupled between the output bus and ground, and a plurality of capacitors coupled between the plurality of switches and the full bridge, wherein one capacitor of the plurality of capacitors is connected to a midpoint of one leg of the full bridge through a switch.

In an MMC-type power conversion device, a control device calculates an evaluation value representing the degree of variations in voltage of capacitors of individual converter cells. When this evaluation value exceeds a threshold value, the control device controls the converter cells as follows: (i) when current in a positive direction flows through a first converter cell with a voltage of the capacitor greater than a mean value, reducing an output time of positive voltage, (ii) when current in a negative direction flows through the first converter cell, increasing an output time of positive voltage, (iii) when current in the positive direction flows through a second converter cell with a voltage of the capacitor smaller than a mean value, increasing an output time of positive voltage, or (iv) when current in the negative direction flows through the second converter cell, reducing an output time of positive voltage.

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.

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.

An energy combiner apparatus is used to convert output of a power supply, and has three output terminals, so that output ports are increased. In the three output terminals of the energy combiner apparatus, a voltage of 1500 V is output between a first output terminal and a second output terminal, a voltage of 1500 V is also output between the second output terminal and a third output terminal, and a total of 3 kV is output. Therefore, an overall output voltage is increased in a case of equal output power. Because the overall output voltage is increased, a current transmitted on a cable may be reduced. Therefore, a thinner cable may be used, so that costs of the cable are reduced. In addition, four cables conventionally required for connecting to the output terminals of the energy combiner apparatus are reduced to three, so that quantity and costs are reduced.