Abb Schweiz Ag

Hitachi Energy Switzerland Ag

Abb Power Grids Switzerland Ag

Christopher Townsend

Hector Zelaya De La Parra

Alireza Nami

Frans Dijkhuizen

Tomas Tengner

A converter arrangement for an AC system includes a phase leg including a first sub-converter, a second sub-converter, an IPT interface configured for connecting the first and second sub-converters with a phase line A, and at least one DC bus connected to the first and second sub-converters. The first sub-converter is connected in parallel with the second sub-converter between the DC bus and the IPT interface. Each of the first and second sub-converters includes a chain-link converter connected to the IPT interface and including a plurality of converter cells connected in series with each other, and a common DC link multilevel converter connected to the DC bus and in series with the chain-link converter.

Converter for an AC system

An energy storage system (ESS) for an electrical system includes an energy storage, and a converter interface arranged for connecting the energy storage to the electrical system. The converter interface includes a modular multilevel converter in which each phase leg includes a plurality of series connected cells of which at least one is a half-bridge cell and at least one is a full-bridge cell.

Energy storage system comprising a modular multi-level converter

A switching cell for a chain link includes a first side including a first terminal and a second terminal, a second side including a third terminal and a fourth terminal, a first switching unit, a second switching unit, and a first and a second capacitor unit. The first terminal is connected to the second terminal via the first capacitor unit. The first capacitor unit has its positive side facing the first terminal. The third terminal is connected to the fourth terminal via the second capacitor unit. The second capacitor has its positive side facing the fourth terminal. The second terminal is connected to the fourth terminal via the second switching unit. The switching cell also includes a third capacitor unit, and the first terminal is connected to the third terminal via a first series connection including the first switching unit and the third capacitor unit. The third capacitor unit has its positive side facing the third terminal. A switching module includes at least one such switching cell. The switching module can include at least two such switching cells, wherein the first switching cell and the second switching cell are connected in series in opposing directions, and wherein the second side of the first switching cell is connected to the second side of the second switching cell. A chain link including a number of switching modules in serial connection is also provided.

Switching cell, a switching module for a chain link, and a chain link for a multilevel converter

A method of controlling a multilevel converter, a computer program and a controller for a converter is provided. The method includes determining a transition voltage from a control period to a following control period, analyzing the switching cells of each phase leg, selecting capacitors to provide the transition voltage and synthesize the output voltage for the following control period, and connecting the selected capacitors during the following control period. The analyzing of each switching cell includes analyzing a first switching leg and a second switching leg of the switching cell. The method includes determining whether a change of state of the first switching leg would contribute to the direction of the transition voltage, and determining whether a change of state of the second switching leg would contribute to the direction of the transition voltage, and determining the internal conditions of each of the first and the second switching leg that are determined as contributing to the transition. Thus, the two legs of the H-bridge are analyzed separately. The selecting of capacitors is performed by selecting the capacitors of the switching legs of the phase leg for the transition voltage on the basis of the determined internal conditions of the switching legs, including comparing the internal conditions of all the switching legs of the phase leg. A controller is configured to control the multilevel converter by performing the method.

Method of controlling the switching of a multilevel converter, a controller for a multilevel converter, and a computer program for controlling a converter

A converter arrangement and a method of controlling a three-phase converter arrangement connected to a transmission grid are provided. The converter arrangement includes three phase legs and an energy transfer circuit. The method includes providing a varying respective output phase voltage to the transmission grid by selecting energy storage elements of both the phase legs and the energy transfer circuit and connecting the selected energy storage elements to the transmission grid output. The method further includes selecting energy storage elements for performing a transfer of energy between the energy storage elements during the control period.

Converter arrangement for power compensation and a method for controlling a power converter

A multi-level power converter includes switching cells, each comprising switching devices and an energy storage element. The switching cells include switching cells of a first type and switching cells of a second type. The converter includes, for each phase, a first arm of serial connected switching cells and a second arm of serial connected switching cells, which first arm and second arm are connected in parallel. The first arm includes more switching cells of the first type than switching cells of the second type and the second arm includes more switching cells of the second type than switching cells of the first type. The switching cells of the first type have lower conduction loss than the switching cells of the second type. The converter is arranged so that a larger current flows through the first arm than the second arm.

Growing community of inventors

Newcastle, Australia

Christopher Townsend