Accordingly, the embodiments herein provide a hybrid modular multilevel converter. The hybrid modular multilevel converter includes one or more chain links, one or more high voltage switches and a plurality of inductors. The one or more chain links are formed by sub modules. The one or more high voltage switches are formed by semi-controlled devices or fully controlled or any other suitable semiconductor devices. The plurality of inductors are arranged in the one or more chain links to limit circulating current among the one or more chain links. The one or more chain links are configured to enhance a power handling capability of the hybrid modular multilevel converter.

Accordingly, the embodiments herein provide a hybrid modular multilevel converter. The hybrid modular multilevel converter includes one or more chain links, one or more high voltage switches and a plurality of inductors. The one or more chain links are formed by sub modules. The one or more high voltage switches are formed by semi-controlled devices or fully controlled or any other suitable semiconductor devices. The plurality of inductors are arranged in the one or more chain links to limit circulating current among the one or more chain links. The one or more chain links are configured to enhance a power handling capability of the hybrid modular multilevel converter.

A protection device is disclosed which may comprise a first sensor, a first switch or a controller. The first sensor may be coupled to a first busbar of busbars and may be configured to measure a respective first electrical characteristic of the first busbar. The first switch may be connected between the first busbar and a reference terminal. The first switch may be configured to connect or disconnect the first busbar to and from the reference terminal. The controller may be coupled to the first sensor and to the first switch and may be configured to control the first switch to connect the first busbar to the reference terminal (e.g., based on the measurement of the first electrical characteristic indicating a change in the first electrical characteristic).

A protection device is disclosed which may comprise a first sensor, a first switch or a controller. The first sensor may be coupled to a first busbar of busbars and may be configured to measure a respective first electrical characteristic of the first busbar. The first switch may be connected between the first busbar and a reference terminal. The first switch may be configured to connect or disconnect the first busbar to and from the reference terminal. The controller may be coupled to the first sensor and to the first switch and may be configured to control the first switch to connect the first busbar to the reference terminal (e.g., based on the measurement of the first electrical characteristic indicating a change in the first electrical characteristic).

The present power conversion device includes an inverter, a step-up/down converter, a first capacitor, a second capacitor, a voltage sensor, a control device, and a backup power supply. The auxiliary device is connected between the first DC power supply and the step-up/down converter, and the control device includes an abnormality determination unit configured to determine that an abnormality has occurred when a control voltage is equal to or lower than a first threshold value, and a control unit configured to execute discharge control when the abnormality determination unit determines that the abnormality has occurred and an inter-terminal voltage measured by the voltage sensor is equal to or lower than a second threshold value.

The present power conversion device includes an inverter, a step-up/down converter, a first capacitor, a second capacitor, a voltage sensor, a control device, and a backup power supply. The auxiliary device is connected between the first DC power supply and the step-up/down converter, and the control device includes an abnormality determination unit configured to determine that an abnormality has occurred when a control voltage is equal to or lower than a first threshold value, and a control unit configured to execute discharge control when the abnormality determination unit determines that the abnormality has occurred and an inter-terminal voltage measured by the voltage sensor is equal to or lower than a second threshold value.

A drive circuit for driving an electro-optical device like an optically switchable glazing, e.g. a glass panel provided with a PDLC or SPD layer, comprises a set of input terminals for receiving an alternating input voltage at a first frequency; a set of output terminals for supplying an alternating output voltage at a second frequency; a control circuit generating a control signal dependent on an input signal, the input signal representing a charge state of the electro-optical device; and a current-direction circuit for controlling a current-flow direction of an electrical current in response to the control signal. The control circuit and the current-direction circuit are thereby configured to control the second frequency such that the electro-optical device is prevented from degradation, while keeping an energy consumption low.

A multilevel converter comprising a first switching branch connected between a positive DC-link terminal and an AC output terminal and comprising series-connected first and second switching elements, a second switching branch connected between the AC output terminal and a negative DC-link terminal and comprising series-connected third and fourth switching elements, a third switching branch connected between a DC-link neutral point and a connection point of the first and the second switching elements, a fourth switching branch connected between the DC-link neutral point and a connection point of the third and the fourth switching elements, the fourth switching branch being completely independent from the third switching branch, and a flying capacitor connected between the connection point of the first and the second switching elements and the connection point of the third and the fourth switching elements.

A multilevel converter comprising a first switching branch connected between a positive DC-link terminal and an AC output terminal and comprising series-connected first and second switching elements, a second switching branch connected between the AC output terminal and a negative DC-link terminal and comprising series-connected third and fourth switching elements, a third switching branch connected between a DC-link neutral point and a connection point of the first and the second switching elements, a fourth switching branch connected between the DC-link neutral point and a connection point of the third and the fourth switching elements, the fourth switching branch being completely independent from the third switching branch, and a flying capacitor connected between the connection point of the first and the second switching elements and the connection point of the third and the fourth switching elements.

A power converter includes a plurality of converters which are connected in parallel to a DC power supply in which an operating point is changed in accordance with an output current or an output voltage. The plurality of converters include maximum power point tracking units for performing maximum power point tracking calculations of the DC power supply. Results of the maximum power point tracking calculations of the plurality of converters are unified between the plurality of converters and the plurality of converters are controlled based on the unified calculation result.