US 12,231,060 B2
Voltage source converters for power conversion in a HVDC power transmission network
Pablo Briff, Stafford (GB); Andrzej Adamczyk, Stafford (GB); and Sameer Singhal, Stafford (GB)
Assigned to GE INFRASTRUCTURE TECHNOLOGY LLC, Greenville, SC (US)
Appl. No. 17/998,793
Filed by General Electric Technology GmbH, Baden (CH)
PCT Filed May 28, 2021, PCT No. PCT/EP2021/064396
§ 371(c)(1), (2) Date Nov. 14, 2022,
PCT Pub. No. WO2021/244979, PCT Pub. Date Dec. 9, 2021.
Claims priority of application No. 20275099 (EP), filed on Jun. 1, 2020.
Prior Publication US 2023/0344364 A1, Oct. 26, 2023
Int. Cl. H02M 7/483 (2007.01); H02M 1/00 (2006.01)
CPC H02M 7/4835 (2021.05) [H02M 1/0012 (2021.05); H02M 1/0025 (2021.05)] 11 Claims
OG exemplary drawing
 
1. A voltage source converter, for power conversion between AC and DC in a HVDC power transmission network, comprising:
first and second DC terminals for connection to a DC network and having at least one converter limb extending therebetween, the or each converter limb including first and second limb portions separated by a corresponding AC terminal for connection to a respective phase of an AC network, each limb portion including a chain-link converter extending between the associated AC terminal and a corresponding one of the first or the second DC terminal, and each chain-link converter including a chain-link converter controller programmed to control a plurality of series connected chain-link modules each having a plurality of switching elements connected in parallel with an energy storage device, whereby each chain-link converter is controllable to provide a stepped variable voltage source; and
a voltage source converter controller arranged in operative communication with each chain-link converter controller to coordinate operation of the chain-link converters;
at least one chain-link converter controller being programmed to establish at a first time instant a total voltage sum of all energies stored by the energy storage devices in each chain-link converter within the voltage source converter, and to send the established total voltage sum to the voltage source converter controller;
the voltage source converter controller being programmed to establish a modulation index demand for each chain-link converter, each modulation index demand corresponding to a chain-link converter voltage reference that the corresponding chain-link converter is required to produce divided by the received total voltage sum, and further being programmed to send the established modulation index demand to each corresponding chain-link converter controller; and
each chain-link converter controller being further programmed to reconstruct, from the received modulation index demand, the chain-link converter voltage reference that the chain-link converter it is controlling and is required to produce; wherein the chain-link converter voltage reference is reconstructed by multiplying the received modulation index demand by the total voltage sum established at the first time instant.