Control and dynamic analysis of a parallel‐connected single active bridge DC–DC converter for DC‐grid wind farm application

Abstract

This study presents a control strategy and its dynamic analysis of a high-power dc-dc converter, which is constructed with the parallel-connected single active bridge (SAB) dc-dc converters for dc-grid wind farm applications. The structural and operational characteristics of the SAB dc-dc converter have several advantages for high-power applications, and the modular concept of the parallel-connected converter is highly beneficial especially for offshore wind farm applications in terms of maintenance cost and fault tolerance. To justify the feasibility of the parallelconnected SAB dc-dc converter for dc-grid wind farm applications, an input voltage control method based on the PI control will be introduced and the dynamics of the overall system will be analysed. The analysis results are to be verified by means of simulations and experiments.

Operational Principles of Three-Phase Single Active Bridge DC/DC Converters Under Duty Cycle Control

“…There have already been many studies about the operational principles of DAB converters including single-phase DAB (1p-DAB) [12] and three-phase DAB (3p-DAB) [13] converters under different phase-shift control methods. There are also some studies about the operation of single phase SAB (1p-SAB) converters [14], [15]. However, when moving to threephase SAB (3p-SAB) converters, only a few papers about the operation of 3p-SAB converters could be found [17]- [19].…”

“…The six currents, d 2 and ∆ d can therefore be solved according to the first 8 equations in Table III. As a result, variables can be solved and the results are given as (13), (14) and (15). For the sake of brevity, only i 0 is shown here and the rest currents can be derived according to Table III.…”

“…I SOLATED DC/DC converters are widely applied in many energy conversion applications, thanks to the galvanic isolation, high step-up ratios, compact design and high efficiency [1]- [6]. Two converter types: Dual Active Bridge (DAB) converters [7]- [13] and Single Active Bridge (SAB) converters [7], [14]- [19] are the most popular converter choices among all isolated DC/DC converters. An isolated DC/DC converter normally combines two converter bridges and an intermediate transformer, and it can be designed single-phase [7]- [10], [14]- [16] or three-phase [11]- [13], [17]- [19].…”

“…Other advanced PS control methods such as dual-phase-shift (DPS) [2], extened-phase-shift (EPS) [23] and triple-phase-shift (TPS) [24] are also proposed to improve the efficiency or reduce the transformer reactive power. However, in SAB converters only the active bridge duty cycle [14], [25] can be independently changed and the power can only be transferred from the active to the passive bridge. Thus, it is suggested to use the duty cycle as the control variable and this method is called duty cycle control.…”

Multifrequency approximation and average modelling of an isolated bidirectional dc–dc converter for dc microgrids

“…DC microgrids have attracted worldwide attention due to the development of distributed generation technologies in recent years [1][2][3]. The dc nature of renewable energy sources (e.g.…”