Active and reactive power regulation in grid connected wind energy systems with permanent magnet synchronous generator and matrix converter

Abstract

This study presents a simple voltage oriented vector control scheme to regulate active and reactive power in a grid connected variable speed wind electrical system that consists of permanent magnet synchronous generator and matrix converter, which enables the maximum power tracking in wind electrical systems. The maximum extractable power from wind is derived from power curves and set as reference active power. Reactive power reference is chosen as zero. The deviations in powers are processed by proportional and integral (PI) controllers which vary the voltage gain of MC through which the desired regulation of powers is carried out. Since the relationship between wind speed and reference active power is nonlinear, single PI controller is insufficient, hence gain scheduling is required to adjust the controller parameters in response to changes in wind speeds. The controller parameter change is abrupt in conventional gain scheduling which leads to unstable performance. To avoid this, neural network-based PI (NN-PI) is designed which is more robust. In the presented work, both conventional gain scheduled PI and NN-PI are applied to validate the suggested voltage oriented control for power regulation. Simulation and experimental studies are presented to confirm the effective functionality of the system.

Z‐source matrix rectifier

“…It can be seen from Fig. 8 that the capacitor voltage V C and output voltage V dc are 26.5 V which is closed to the theoretical value 27 V calculated from (9) and (13). Then, from (12) and 14, we get the voltage transfer ratio G = 0.779 and the boost factor B = 1.125.…”

“…Since the MR is the front-end rectification stage for indirect MCs, MRs and MCs share some same advantages such as input current with low harmonic content [1,2], controllable input power factor [3] and bidirectional energy flow [4]. The circuit has some potential applications and has recent attention in the field of power electronics [2,[5][6][7][8][9][10]. For the high-voltage ac-ac applications, the Z-source MC is presented and researched such as the modulation strategies [11] and motor drives [12].…”

Quasi-Z-source matrix converters to be used in PMSG-based WECS: Modeling, control, and comparison

“…As conditioning interface between the generator and the grid or load, power electronics play a prominent role in a variable WECS. Various power electronic solutions have been proposed in literature for the variable‐speed PMSG‐based WECSs in high, medium, and low power levels . In Amei et al, a simple low‐cost configuration integrating a diode rectifier, a boost chopper, and a voltage source inverter (VSI) was proposed for low power levels (LPLs).…”

“…In Ng et al, a power electronic solution employing a multilevel cascaded voltage source converter was developed for a transformer‐less WECS, capable of delivering lower cost, high reliability, and fault tolerance for lightweight, direct drive air‐cored or iron‐cored slotless generators for large wind turbines. Matrix converter (MC) has also received increasing attention in recent years, and is proposed to be used as the grid interface of a PMSG‐based WECS, in low‐power microgrids and local applications …”

“…MC is a single‐stage forced‐commuted ac/ac conversion system without any energy storage element which features sinusoidal input current and output voltage, and a controllable input power factor . Due to the lack of energy storage element, the MC is expected to be more reliable, and smaller in size, compared to conventional back‐to‐back converter . Employing the MC in a PMSG‐based WECS (MC‐PMSG‐WECS) makes it possible to eliminate the rectifying stage which, in turn, results in a gear‐less, compact, and reliable single‐stage configuration favored over other variable‐speed WECSs, especially in LPLs …”