Switched Reluctance Generator for Low Voltage DC Microgrid Operation: Experimental Validation

Abstract

This paper presents the control of a Switched Reluctance Generator (SRG) for low voltage DC grid with the objective of efficiency maximizing. Analysis of the energy conversion, including electrical machine losses (Joule, magnetic, mechanical) and power converter losses (switching and conduction), has shown that there is an optimal combination of control variables (turn-on and conduction angles, phase current reference), which maximizes the drive efficiency. The control variables are derived from a Finite Element Analysis and parametric optimization algorithm for all of the operating points in the torque-speed plane and stored in lookup tables. The performances are evaluated with intensive numerical simulations and experimental tests with a 8/6 SRG feeding a DC resistive load for different rotational speeds. The results show good performances of the output DC voltage control with low ripples, even in the presence of speed and load variations. Thanks to the optimization, simulation results show that beyond 1500 rpm, drive efficiency is higher than 60 % and almost reaches 70 % at nominal speed. The experimental results show that, for light loads and beyond rated speed, the drive efficiency lies in the range between 60 % and 80 % .

Integration of Switched Reluctance Generator in a Wind Energy Conversion System: An Overview of the State of the Art and Challenges

“…Long settling time and controller parameters cannot be optimized with different operating conditions [33,35,57] Sliding Mode (SM)…”

“…In hard switching, there are two modes of operation: excitation and generation. In soft switching, there are three modes of operation: excitation, fly-wheeling, and generation [35]. This last commutation strategy is one of the most used, with applications in different fields, such as in WECS, the automotive industry, and aerospace, due to the high flexibility and the independence of phase control [36].…”

“…Consequently, this method of PI control has a good ability to respond to varying wind speeds and loading conditions, which makes the system even more attractive for wind generation systems. A control of SRGs for low voltage Dc micro-grid was presented in [35]. The analysis of the energy conversion to achieve the maximum drive performance is presented taking into consideration the electrical machine, power converter losses, and the external excitation source.…”

Improvement of Steady State Performance of Voltage Control in Switched Reluctance Generator: Experimental Validation

“…At steady-state operation, it is expected that the capacitor can hold the current variations created by the magnetization and the generation of current in the SRG, resulting in a no-use of the DC power source. The voltage equation of each SRG phase is given by [27]:…”

Efficiency Enhancement of Switched Reluctance Generator Employing Optimized Control Associated with Tracking Technique

“…As an example, ref. [11] presents experimental results for validating the SRG in operation on a low-voltage DC microgrid. In these cases, it is appropriate to use generators that provide high efficiency to enhance the power generation.…”