A cascaded brushless doubly fed induction generator for wind energy applications based on direct power control

Abstract

This paper proposes a direct power control (DPC) strategy for cascaded brushless doubly fed induction generator (CBDFIG), which eliminates the slip rings and brushes in conventional DFIG wind turbine systems and features quick dynamic response and excellent steady state performance. Prior methods for controlling CBDFIG are based on vector control (VC), which is complicated and requires much tuning work and machine parameters. Appropriate decoupling and fine PI tuning are mandatory to obtain good performance over the entire operating range. Furthermore, there are few papers regarding the grid synchronization issue of CBDFIG. This paper firstly analyzes the influence of each voltage vector on active/reactive powers and then proposes a unified switching table for both grid-connected operation and grid synchronization process. The effectiveness of the developed DPC method for CBDFIG is confirmed by the presented simulation results.

Model predictive virtual power control of brushless doubly‐fed induction generator for fast and smooth grid synchronisation

“…Figs. 9 and 10 illustrate the simulation results of DPC in [18] and VC in [16], respectively. The results in Figs.…”

“…However, most of the studies have addressed the control issues of BDFIG in either standalone or grid-connected operation. So far, only a few works have been conducted about the process of grid synchronisation [16][17][18]. In [16], a grid synchronisation controller of BDFIG based on PW flux-oriented vector control was presented, where an outer PW voltage-loop and an inner CW current-loop are applied.…”

“…In [17], a direct virtual torque control method for grid synchronisation of BDFIG was proposed, it unifies the control structure between the grid synchronisation mode and the grid‐connected mode, and can achieve smooth and fast grid synchronisation. Based on similar switching table principle in [17], a direct power control (DPC) for BDFIG was proposed in [18], but only numerical simulation was provided. To the authors’ best knowledge, the control issue of grid synchronisation controller for BDFIG has not been fully analysed so far.…”

Indirect Vector-Controlled Brushless Doubly-Fed Twin-Stator Induction Generator for Wind Energy Conversion Application

“…BDFTSIG applications have recently witnessed booming interest especially in the past 10 years [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. A high performance vector control based technique was elaborated showing acceptable performance yet at the penalty of less tolerance to machine parameters' variation [7].…”

“…Preserving the required performance and the need for an estimator, improved machine construction was performed with nested rotor loops [9,10]. The evolution of direct power control strategy established high performance operation and better transient response with noticeable ripples in injected active/reactive power due to the lack of accurate decoupling [11][12][13]. The utilization of artificial intelligence-based converter controllers enables fewer ripples in the injected power with high complexity in the controller implementation as improved direct torque control [14,15], sliding mode control [16], model reference adaptive control [17], and model predictive current control [18,20].…”