A series HVDC power tap using modular multilevel converters

Li, Binbin; Guan, Mingxu; Xu, Dianguo; Li, Rui; Adam, Grain Philip; Williams, B.W.

doi:10.1109/ecce.2016.7854775

Cited by 7 publications

(6 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The objective of energy management is twofold: maintain the sum of ETs and EBs equal * , shown in (14), and keep the difference between them to zero, given in (15).…”

Section: Energy Management and Control Schemementioning

confidence: 99%

“…It can be seen that energy deviations from the ac and dc terms are zero over an operation cycle without extra balancing control. The stack energy of this converter is naturally balanced if the original state satisfies the conditions in (14) and (15). A transient energy drift or an initially unbalanced state can be corrected by adding an extra dc component Δidc and an ac component ±Δiac/2rT into the stack currents and thereby the stack energy exchanges are adjusted according to (17).…”

Section: Energy Management and Control Schemementioning

confidence: 99%

“…When this converter serves as a dc tap for LPHR applications, the overall step-ratio is very high and the power throughput is expected to be less than 10% of the transmission link power [8], [13], [14]. For this application, the transformer power rating and voltage rating (less than 20 kV) will be much smaller than that in the front-to-front configuration for interconnecting two different HVDC links (more than 400 kV) [4], [5], [27].…”

Section: Flexible Step-ratio Rangementioning

confidence: 99%

“…Although there is no full-scale practical project for dc tap up to date, it has attracted much interest in recent years for both academic research and industrial development to satisfy the demand and architecture for future dc grids [10]- [16]. It could collect power from small-scale offshore wind farms (OWF) near the cable routes by tapping into the HVDC link directly [10], [11], and the LPHR conversion can also tap out a small fraction of the link power to service demand in remote communities with inadequate ac supplies but which are crossed by the HVDC corridors [12]- [14]. A growing role for conversion between HVDC and Medium Voltage Direct Current (MVDC) grids is also anticipated [15], [16].…”

mentioning

confidence: 99%

See 3 more Smart Citations

A Compact Modular Multilevel DC–DC Converter for High Step-Ratio MV and HV Use

Xiang

Zhang

Luth

et al. 2018

IEEE Trans. Ind. Electron.

View full text Add to dashboard Cite

In multi-terminal dc networks or future dc grids, there is an important role for high step-ratio dc-dc conversion to interface a high voltage network to lower voltage infeeds or offtakes. The efficiency and controllability of dc-dc conversion will be expected to be similar to modular multi-level ac-dc converters. This paper presents a modular multilevel dc-dc converter with a high step-ratio for medium voltage and high voltage applications. Its topology on high-voltage side is derived from the half-bridge single-phase inverter with stacks of sub-modules replacing each of the switch positions. A near-square-wave current operation is proposed which achieves near-constant instantaneous power for single-phase conversion, leading to reduced stack capacitor and filter volume and also increased the power device utilization. A controller for energy balancing and current tracking is designed. The soft-switching operation on the low-voltage side is demonstrated. The high step-ratio is accomplished by combination of inherent half-bridge ratio, sub-module stack modulation and transformer turns-ratio, which also offers flexibility to satisfy wide-range conversion requirement. The theoretical analysis of this converter is verified by simulation of a full-scale 40MW, 200 kV converter with 146 sub-modules and also through experimental testing of a down-scaled prototype at 4.5 kW, 1.5 kV with 18 sub-modules. Index Terms-Modular multilevel converter, compact volume, high step-ratio, dc grids. NOMENCLATURE Ch Control headroom D Duty-cycle of the near-square-wave ES Sum of the energy stored in all capacitors ETs, EBs Energy stored in the top stack and bottom stack fo, fs Operation frequency, switching frequency fr SM sorting and selection frequency iBac AC component of the bottom stack current Manuscript

show abstract

“…The objective of energy management is twofold: maintain the sum of ETs and EBs equal * , shown in (14), and keep the difference between them to zero, given in (15).…”

Section: Energy Management and Control Schemementioning

confidence: 99%

Section: Energy Management and Control Schemementioning

confidence: 99%

Section: Flexible Step-ratio Rangementioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

A Compact Modular Multilevel DC–DC Converter for High Step-Ratio MV and HV Use

Xiang

Zhang

Luth

et al. 2018

IEEE Trans. Ind. Electron.

View full text Add to dashboard Cite

show abstract

“…A high-voltage DC (HVDC) tapping is used to extract a limited amount of power (up to 10%) from the main HVDC circuit to feed a nearby local three-phase AC network [1][2][3][4][5]. Series and shunt tapping [6][7][8][9] are the main types of HVDC taps. Series taps are rated at the full current of the main HVDC circuit, while the voltage rating is a percentage of the total DC-link voltage (up to 10%).…”

Section: Introductionmentioning

confidence: 99%