Improved low-cost sliding mode control of 4-leg inverter for isolated microgrid applications

Abstract

Summary Isolated microgrids including several sources of clean energy such as photovoltaic system can be considered as the auxiliary source of power generation. However, unbalanced condition is inevitable in typical microgrids due to asymmetric power generation and consumption. To supply load from different distributed generation, an interface 4‐wire power converter is essential. A 4‐leg inverter with suitable control method is a beneficial solution to support unbalanced loading condition. However, high reliable low‐cost control method achieves more attention to avoid any power outage. As a result, a low‐cost sliding mode control method is proposed in this paper to control the output voltages of the 4‐leg inverter. The proposed method can provide fast dynamic response, fixed switching frequency, high robustness against model parameter mismatches, and external disturbances without any current sensors. Furthermore, to reduce the chattering of the sliding mode control method more effectively, an improved low‐cost method with adaptive discrete coefficient is also proposed. Finally, to evaluate the performance of the proposed method, a 3‐kW test bench with digital control board based on TMS320F28335 processor is provided.

Modeling, design, and experimental test of a zero‐sequence current electromagnetic suppressor

“…[7][8][9][10][11][12][13][14] Specific investigations reveal that the currents that circulate through the neutral conductor are predominantly characterized by zero-sequence harmonic currents, also called triplen harmonics (ie, 3 rd , 9 th , 15 th , ...). [7][8][9][10][11][12][13][14] Specific investigations reveal that the currents that circulate through the neutral conductor are predominantly characterized by zero-sequence harmonic currents, also called triplen harmonics (ie, 3 rd , 9 th , 15 th , ...).…”

“…Sometimes, these harmonic currents reach values higher than the fundamental component. [10][11][12][13][14][15][16][17][18] The use of electromagnetic devices has shown to be a promising alternative for the reduction of harmonic components, namely the triplen harmonics, which have a strong zero-sequence concentration. [13][14][15][16][17] In the last years, different techniques, active and passive, have been applied aiming at the elimination or reduction of the zero-sequence harmonic currents in four-wire power systems.…”

“…Under these conditions, power grids that supply loads with nonlinear characteristics usually have high currents flowing through the neutral conductor. [7][8][9][10][11][12][13][14] Specific investigations reveal that the currents that circulate through the neutral conductor are predominantly characterized by zero-sequence harmonic currents, also called triplen harmonics (ie, 3 rd , 9 th , 15 th , ...). Sometimes, these harmonic currents reach values higher than the fundamental component.…”

A multistage H‐infinity–based controller for adjusting voltage and frequency and improving power quality in islanded microgrids

“…33 There are several control methods used to adapt the system voltage and frequency values for islanded MGs. These control methods are divided into noncommunication-based control methods [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] and communication control methods. [25][26][27][28][29] The first one includes droop control, peer-to-peer control, hierarchical control, PI/PID control, and sliding mode control.…”

Resilient cyber physical infrastructure for single‐phase dual inverter with sliding mode control

“…Generally, the control of inverter is achieved by PI, PID, and direct power control. The sliding mode control (SMC) 22,[31][32][33][34][35][36][37][38] provides the dynamic response to the nonlinear systems with the property of hysteresis. The steady-state error of the system is low compared with other controllers.…”