Reducing of total harmonic distortion by simulating passive filters to suppress harmonic currents with the case: Faculty of Engineering Building, Universitas Kristen Indonesia Jakarta

Today’s electrical appliances use power electronics to save electricity. However, this equipment generates non-sinusoidal current, causing wave defect, expressed as total harmonic distortion (THD). As the %THD increases, the greater risk of equipment damage. For this reason, the research was carried out in the Faculty of Engineering Building, Universitas Kristen Indonesia Jakarta (FT UKI Jakarta) where there are many load combinations such as computers, various types of lights, laboratory equipment such as transformers, electric motors and so on. The research was conducted using quantitative method. Data collection is carried out directly in the main panel. Based on the measurement results, the calculation of the maximum load current (IL) and short circuit (ISC) is carried out. Through these values, it can be seen that whether the odd dominant harmonic values and orders meets the IEEE 519-2014 standards or not. Calculations and analysis of the measurement results have shown that the %THDI in the FT UKI building has not meet the standard. Therefore, it is necessary to simulate the filter design to reduce the %THDI, so that the results can meets the IEEE 519-2014 standard, which is below 5%.

Investigation of 2DOF PID Controller for Physio-Therapeutic Application for Elbow Rehabilitation

The aim of this work is to evaluate the output of a two-degree of freedom (DOF) proportional integral derivative (PID) controller for controlling elbow flexion and extension on an upper limb rehabilitation robot of an existing model. Since the usage of upper limb rehabilitation is increasing dramatically because of human impairment, 2DOF has been proposed in this work as a suitable controller. The 2DOF PID controller offers set-point-weight features and, hence, is fast in removing disturbance from the system and ensuring system stability. Importantly, as the system parameters are unknown in this work, the black-box model approach has been taken into consideration, using the MATLAB System identification toolbox to estimate a model. The best-fitted estimated model is then coupled with the proposed controller in the MATLAB/Simulink environment that, upon successful simulation works, leads, finally, to the hardware implementation. Three different amplitudes of sinusoidal current signals, such as 0.3 amps, 0.2 amps, and 0.1 amps, are applied for hardware measurements. Considering patients’ physical conditions. In this work, the 2DOF controller offers a fast transient response, settling time, negligible tracking error and 0% overshoot and undershoot.

Locking Phenomena in Semiconductor Lasers near Threshold with Optical Feedback and Sinusoidal Current Modulation

The dynamics of semiconductor lasers with optical feedback and current modulation has been extensively studied, and it is, by now, well known that the interplay of modulation and feedback can produce a rich variety of nonlinear phenomena. Near threshold, in the so-called low frequency fluctuations regime, the intensity emitted by the laser, without modulation, exhibits feedback-induced spikes, which occur at irregular times. When the laser current is sinusoidally modulated, under appropriate conditions, the spikes lock to the modulation and become periodic. In previous works, we studied experimentally the locked behavior and found sub-harmonic locking (regular spike timing such that a spike is emitted every two or three modulation cycles), but we did not find spikes with regular timing, emitted every modulation cycle. To understand why 1:1 regular locking was not observed, here, we perform simulations of the well-known Lang–Kobayashi model. We find a good qualitative agreement with the experiments: with small modulation amplitudes, we find wide parameter regions in which the spikes are sub-harmonically locked to the modulation, while 1:1 locking occurs at much higher modulation amplitudes.

A Three-Phase Resonant Boost Inverter Fed Brushless DC Motor Drive for Electric Vehicles

The present article proposes a three-phase resonant boost inverter (TPRBI) to feed a permanent magnet brushless DC (PMBLDC) motor at the requested torque with low ripples due to the sinusoidal current injected into the PMBLDC motor. PMBLDC motors have the highest torque-to-weight ratio compared to other motors and are the best choice for electric vehicle applications. Conventionally, these motors are driven by voltage source inverters (VSI) with trapezoidal current injection, introducing unwanted torque ripples. Moreover, due to the buck operation of VSI, an extra power conversion stage is required to elevate the battery voltage level to desired DC-link voltage. This extra stage increases the number of components used, complexity of control and decreases the efficiency and reliability of the overall system. TPRBI injects sinusoidal current in the PMBLDC motor in the proposed method, thus minimizing the torque ripples. The proposed inverter also has an inherent voltage boost characteristic, thus eliminating the extra power conversion stage. The single-stage conversion from DC to boosted sinusoidal AC enhances the system reliability and efficiency and minimizes the cost and weight of the system. A MATLAB/Simulink model is presented along with simulation results and mathematical validation. A comparative evaluation of the proposed system with the conventional VSI-fed PMBLDC motor is presented in terms of induced torque ripples.

Real-Time Implementation of an Optimized Model Predictive Control for a 9-Level CSC Inverter in Grid-Connected Mode

The Crossover Switches Cell (CSC) is a recent Single DC-Source Multilevel Inverter (SDCS-MLI) topology with boosting abilities. In grid-connected PV applications, the CSC should be controlled to inject a sinusoidal current to the grid with low THD% and unity power factor, while balancing the capacitor voltage around its reference. These two objectives can be met through the application of a finite control set model predictive control (FCS-MPC) method. Thus, this paper proposes a design of an optimized FCS-MPC for a 9-level grid-tied CSC inverter. The switching actions are optimized using the redundant switching states. The design is verified through simulations and real-time implementation. The presented results show that the THD% of the grid current is 1.73%, and the capacitor voltage is maintained around its reference with less than 0.5 V mean error. To test the reliability of the control design, different scenarios were applied, including variations in the control reference values as well as the AC grid voltage. The presented results prove the good performance of the designed controller in tracking the reference values and minimizing the steady-state errors.