A hybrid Linear Quadratic Regulator (LQR) and Proportional-Integral (PI) control for a MicroGrid (MG) under unbalanced linear and nonlinear loads was presented and evaluated in this paper. The designed control strategy incorporates the microgrid behavior, low-cost LQR, and error reduction in the stationary state by the PI control, to reduce the overall energetic cost of the classical PI control applied to MGs. A Genetic Algorithm (GA) calculates the parameters of LQR with high-accuracy fitness function to obtain the optimal controller parameters as settling time and overshoot. The gain values of the classical PI controller were determined through the improved LQR values and geometrical root locus. When MG operates in the grid-tied mode under unbalanced conditions, the controller performance of the Current Source Inverter (CSI) of the MG is considerably affected. Consequently, the CSI operates in a negative-sequence mode to compensate for unbalanced current at the Point of Common Coupling (PCC) between the MG and the utility grid. The study cases involved the reduction of the negative-sequence percentage in the current at the PCC, mitigation of harmonics in the current signal injected by the MG, and close related power quality issues. All these cases have been analyzed by implementing an MG connected at the PCC of a low-voltage distribution network. A numerical model of the MG in Matlab/Simulink was implemented to verify the performance of the designed LQR-PI control to mitigate or overcome the power quality concerns. The extensive simulations have permitted verifying the robustness and effectiveness of the proposed strategy.

This paper presents the design of a decoupled linear control strategy for a Dynamic Voltage Restorer (DVR) that utilizes a Matrix Converter (MC) as its core element and obtains the compensation energy directly from the power system. This DVR is intended to cope with power quality problems present in supply system voltages such as balanced and unbalanced variations (sags and swells), and harmonic distortion. The dynamic model of the complete system that includes the Matrix Converter, the input filters and the electrical grid, is performed in the synchronous reference frame ($dq0$), to have constant signals at the fundamental frequency, in order to design the proposed linear control strategy. The coupling in the $dq$ components of the system output signals caused by the Park Transformation, is eliminated by a change of variable proposed for the controller design, giving rise to a decoupled linear control. In this way, the strategy developed makes it possible to establish an adequate transient response for the converter in terms of convergence speed and overshoot magnitude, in addition to ensuring closed-loop system stability under bounded operating conditions. Unlike other proposals that utilize complex modulation strategies to control the MC under adverse conditions at the input terminals, in this case, the ability to generate fully controllable output voltages, regardless of the condition of the input signals, is provided by the designed linear controller. This allows the development of a multifunctional compensator with a simple control that could be of easy implementation. In order to verify the performance of the control strategy developed, and the effectiveness of the proposed DVR to mitigate the power quality problems already mentioned, several case studies are presented. The operational capacity of the MC is demonstrated by the obtained simulation results, which clearly reveals the capability of the DVR to eliminate voltage swells up to 50% and sags less than 50%. The compensation limit reached for sags is 37%. In relation to compensation for unbalanced voltage variations, the DVR manages to reduce the voltage imbalance from 11.11% to 0.37%. Finally, with regard to the operation of the DVR as an active voltage filter, the compensator is capable of reducing a THD of 20% calculated on the supply voltage, to a value of 1.53% measured at the load terminals. In the last two cases, the DVR mitigates disturbances to a level below the criteria established in the IEEE standard for power quality. Results obtained from numerical simulations performed in MATLAB/Simulink serve to validate the proposal, given that for each condition analyzed, the MC had succesfully generated the adequate compensation voltages, thus corroborating the robustness and effectiveness of the control strategy developed in this proposal.

In this paper, an efficient implementation of the four-step current commutation technique for controlling bidirectional power switches in a Matrix Converter (MC) is proposed. This strategy is based on the enhanced pulse width modulation peripheral included in the $C2000$ Delfino 32-bit microcontroller of Texas Instruments. By tuning the algorithmic parameters contained in this module, the four-step commutation process is carried out on the Microcontroller Unit (MCU) without overloading the full complex processor and avoiding the use of additional special hardware such as Field-Programmable Gate Arrays (FPGA) or Complex Programmable Logic Devices (CPLD) when controlling the MC. The algorithm is implemented on the TMS320F28379D MCU and operationally validated on an MC prototype, where the functionality of the proposal is demonstrated.

This paper presents a versatile, low-cost real-time control platform with embedded isolated inputs and outputs for direct usage in electrical applications. The inputs correspond to voltage and current measurements, while the outputs are digital signals with isolated power supply. The validation for the platform considers the implementation of the power electronics topologies where the control algorithms are implemented in Simulink. The topologies are the interleaved three-phase buck converter, push–pull converter, H-bridge, and thyristor-based AC load controller. The control for them involves voltage feedback, current feedback, linear control algorithms, and the implementation of a discrete PLL algorithm for the last topology. Hence, the platform demonstrates the effectiveness of performing real-time control for some power electronics topologies.