The growing need for highly reliable and efficient power supply of renewable energy resources and new sizeable loads necessitated novel ways to transfer electric power between them. In the current configuration, transformers are passive devices that do not enable dc systems to connect of interface the electric grid with other energy grids. With the growth of power devices and power electronic converters, direct current transmission and distribution systems using medium or high voltage provide power flow control between various energy networks. This talk would highlight power electronics technologies for the highly reliable dc transmission and distribution systems. Various configurations of solid-state transformer (SST) would be introduced especially modular multi-cell power converters among the configurations. Special focuses are paid on two different modulation strategies for reducing power losses and providing tolerant ability of switching device failures in modular multilevel converters. 2019 IEEE Conference on Energy Conversion (CENCON) 8 S1-1: Power Quality Room: Ball Room Karaton Time: 13:00 14:00 13:00 The 9-150 kHz Disturbance Characteristics of a Grid-connected Rooftop Photovoltaic System Gusdhi Rhazhya Ramadhan and Budi Sudiarto (Universitas Indonesia, Indonesia) Abstract: The usage of renewable energy is increasing in many countries, Indonesia included. This spike of interest is supported by its environmental-friendly nature and the fact that it is one of the most effective ways to combat global warming. Solar power plants are electricity generators with the ability to convert solar energy to electricity by using solar panels.However, solar power plants are indubitably dependent on solar energy, which can cause a fluctuation of output because solar energy is affected by weather and the cloud's condition.Generally, solar power plants have a power electronics component called an inverter. Inverters are used to convert the output of solar panels, the direct current (DC), to alternating current (AC). The usage of power electronics such as inverters plus the fluctuation of the solar panel commonly cause disturbances .Inverters usually have a switching rate higher than 1 kHz, which can cause disturbance in the range of 9-150 kHz throughout the whole system.However, there is little to none standardization regarding how much emission it is allowed to radiate at the 9-150Khz. With the aforementioned concerns in mind, this writing discusses research regarding the characteristics of disturbance on the 9-150Khz frequency on the On-Grid solar power plants located at SPBU Kuningan .Measurement is done on the output side of the solar inverter. The results of research shows that the disturbance produced remains constant in correlation with changes in irradiance or power, however the disturbance produced increases as the power output changes during a short interval. The usage of renewable energy is increasing in many countries, Indonesia included. This spike of interest is supported by its environmental-friendly nature and the fact that it is one of the most effective ways to combat global warming. Solar power plants are electricity generators with the ability to convert solar energy to electricity by using solar panels.However, solar power plants are indubitably dependent on solar energy, which can cause a fluctuation of output because solar energy is affected by weather and the cloud's condition.Generally, solar power plants have a power electronics component called an inverter. Inverters are used to convert the output of solar panels, the direct current (DC), to alternating current (AC). The usage of power electronics such as inverters plus the fluctuation of the solar panel commonly cause disturbances .Inverters usually have a switching rate higher than 1 kHz, which can cause disturbance in the range of 9-150 kHz throughout the whole system.However, there is little to none standardization regarding how much emission it is allowed to radiate at the 9-150Khz. With the aforementioned concerns in mind, this writing discusses research regarding the characteristics of disturbance on the 9-150Khz frequency on the On-Grid solar power plants located at SPBU Kuningan .Measurement is done on the output side of the solar inverter. The results of research shows that the disturbance produced remains constant in correlation with changes in irradiance or power, however the disturbance produced increases as the power output changes during a short interval. 13:20 Implementation Modified PQ in Single-Phase Harmonic Reduction Using Hybrid Shunt Active Power Filter with Hysteresis Control: Asep Andang (Siliwangi University, Indonesia); Nurul Hiron (University of Siliwangi & UNSIL, Indonesia); Eka Priatna (Siliwangi University, Indonesia) Abstract: The development of the use of nonlinear loads in electric power systems today is due to the extensive use of electronics in equipment in everyday life, resulting in more significant harmonic waves being produced so that it affects the quality of the power system. The harmonic reduction has been made since harmonics are existing in the network starting by using a passive filter then active, and the last is a hybrid filter. In this study will be discussed the use of passive filters connected to the network and shunt connected with active filters (HAPF). The active power filter control is carried out using the hysteresis control to switch the inverter while the use of the modified PQ model is implemented to produce a reference current based on a decomposition of a single phase load current. From the results of the simulation model, there is a decrease in harmonics to 1.45% for inductive nonlinear loads and 1.46% for complex nonlinear loads The development of the use of nonlinear loads in electric power systems today is due to the extensive use of electronics in equipment in everyday life, resulting in more significant harmonic waves being produced so that it affects the quality of the power system. The harmonic reduction has been made since harmonics are existing in the network starting by using a passive filter then active, and the last is a hybrid filter. In this study will be discussed the use of passive filters connected to the network and shunt connected with active filters (HAPF). The active power filter control is carried out using the hysteresis control to switch the inverter while the use of the modified PQ model is implemented to produce a reference current based on a decomposition of a single phase load current. From the results of the simulation model, there is a decrease in harmonics to 1.45% for inductive nonlinear loads and 1.46% for complex nonlinear loads 13:40 An Automatic Single Phase Power Factor Compensator Using Fuzzy and Gain Scheduling Gentri Adiningtyas and Novita Siti Lestari (Diponegoro University, Indonesia) Abstract: Power quality has been much concern of many researchers these days. Power factor compensator is the main topic of this research, as it is can be alternative for increasing efficiency of power quality. Power factor (cos φ) value equal or close to 1 categorized as a good power quality. In this research, an automatic power factor compensator with various capacitor values is proposed. Fuzzy logic controller and gain scheduling are applied, in order to control power factor value maximally. Capacitor value that required can be obtained from control system of the plant. Then, some capacitors will be activated with an algorithm. The software is embedded in low-cost microcontroller which will activate specific capacitor variables as the system needed. In the end of this paper is provided data of prototype performance. Already proved, prototype can compensate power factor quality of the grid. Power quality has been much concern of many researchers these days. Power factor compensator is the main topic of this research, as it is can be alternative for increasing efficiency of power quality. Power factor (cos φ) value equal or close to 1 categorized as a good power quality. In this research, an automatic power factor compensator with various capacitor values is proposed. Fuzzy logic controller and gain scheduling are applied, in order to control power factor value maximally. Capacitor value that required can be obtained from control system of the plant. Then, some capacitors will be activated with an algorithm. The software is embedded in low-cost microcontroller which will activate specific capacitor variables as the system needed. In the end of this paper is provided data of prototype performance. Already proved, prototype can compensate power factor quality of the grid. S2-1: Control of Power Electronics 1 Room: Pemandengan 1 Time: 13:00 14:00 13:00 Modelling and Design of a Current Controller for Light Rail Regenerative Inverter System Chuen Ling Toh and Muhammad Hairi Zainol Hilmi (Universiti Tenaga Nasional, Malaysia); Pei Cheng Ooi (The University of Nottingham Malaysia Campus, Malaysia) Abstract: Three phase voltage source inverter has been proposed to transfer the braking energy of a light rail vehicle back to the utility grid. This solution saves cost in purchasing large number of energy storage modules. However, it raises some concerns on power grid integrity, such as harmonics distortion. Therefore passive filters are normally added to mitigate the harmonics. This paper proposes a grid current controller to minimize the needs of ac filters. The proposed PI controller is stable and shows good dynamic response with the settling time measured at 3.49 ms. In addition, sinusoidal grid currents are produced successfully. The total harmonics distortion index for the grid current is measured at 2.61%. Three phase voltage source inverter has been proposed to transfer the braking energy of a light rail vehicle back to the utility grid. This solution saves cost in purchasing large number of energy storage modules. However, it raises some concerns on power grid
This paper presents the development of multiple-input single-output converter (MISO) with uneven load sharing controller. The premise of this study is to create uneven load current sharing between the converters at different loading conditions in order to maximize the efficiency of the overall MISO converter. The goal is to find a proper ratio of current from each converter to the total load current to achieve the greatest efficiency. The design and operation of the converter was tested and verified through simulation and hardware implementation. Different ratios of current from each converter were used to fully test the MISO converter. For the 5A and 6A load current, the maximum efficiencies were reached with the 70%/30% ratio case, with efficiencies of 94.91% and 95.07%, respectively. For 7A load current, the maximum efficiency was reached with the 60%/40% ratio case, with an efficiency of 94.59%. Results also demonstrate that the efficiency of the unequal current sharing outperforms that obtained from the equal current sharing method.
Technology advancement is currently rising at a rapid rate. This increases the demands for digital electronics industry in Malaysia. However, there is one issue when it comes to electronics, it is susceptible to power disturbance. Power disturbance can be categorized into six types which are transients, interruptions, undervoltage, overvoltage, waveform distortion and voltage fluctuations. In this study, an uninterruptible power supply (UPS) using double-conversion technique is presented due to its ability to provide adequate power conditioning and backup power in power disturbance situation. The simulation and designing of the converters such as rectifier, boost converter and inverter are presented using the MATLAB/Simulink. The simulation results showed that the UPS system was able to provide a continuous power supply with acceptable THD levels.
Electric vehicles generally use a permanent magnet DC motor (PMDC). An example of an electric vehicle using PMDC is the electric scooter. The PI Controller to control the electric scooter scheme has a cascade configuration. The common problem in implementing a PI cascade controller is that the gain does not match the increasing error value in some conditions. There is also a case where a cascaded PI control method uses fuzzy logic controller, commonly called fuzzy gain scheduling. The addition of fuzzy gain scheduling on the PI speed controller shows that the speed graph response of the PMDC is better than the speed response without fuzzy gain scheduling. This method can give a good performance.
A direct-drive system with a permanent magnet linear generator has been an attractive solution for wave energy converter devices. Exploiting the reciprocating movement of wave motion has enabled the application of linear generators to wave energy converter devices. This paper presents the computational simulation of the Permanent Magnet Linear Generator design for a point absorber wave energy converter. The electromagnetic analysis was done using the Finite Element Analysis software, ANSYS. With this analysis, results on the flux distribution, air gap flux density and open-circuit results of the proposed design were gathered. A lab-scale device was constructed to validate a simple version of a single-phase linear generator design. A comparative study of both simulation and experimental results of the linear generator was carried out. Based on the results, the percentage error between simulation and experimental obtained was acceptable. To maximize power generation, an improved version of the linear generator based on an actual ocean profile was proposed.
Hybrid systems are counted as the best alternatives for environmental and power difficulties. To optimize any system in order to attain an economic system with a lower cost, sizing is required. In addition, an Energy Management Strategy (EMS) for controlling the flowing power in the system to supply the load is required. A metaheuristic optimization algorithm called Cuckoo Search Algorithm (CSA) is complemented with EMS to control and solve optimization problems for the residential area in Tripoli-Libya. In order to increase the utilization of renewable energy sources (RESs) as Photovoltaic (PV) and Wind Turbine (WT), a microgrid system was proposed with the aforementioned RESs, with battery (BT) and, Electric Vehicle (EV) in terms of Vehicle-to-Grid (V2G). The sizing of the components is performed to attain the proposed objective that termed Renewable Energy Fraction (REV) to be increased. The area of study is fortunate with different climatology conditions to produce energy through different seasons. The result demonstrated that the objective function has been achieved due to the high potential of RES in the study area. The proposed method could provide a system with a fewer number of components. The proposed system may be helpful in reducing the dependency on the utility grid by using the RESs and improving the standard of living of human beings.
Power System Stabilizers (PSSs) are utilized to improve the stability of electrical networks and provide additional damping to reduce electromechanical oscillations. PSS is developed to cope with different oscillation modes, such as global, local, and inter-area modes. Several PSS designs have been discussed in the literature, including single input, dual-input and Multi-Band (MB) PSS. In this research, different PSSs designs (PSS1A, PSS3B, and MB-PSS4B) are investigated, and a four-machine system is considered with two areas and modeled using MATLAB/Simulink. The results indicate that the performance of optimized MB-PSS4B is better than PSS1A and PSS3B where the settling time of power angle is reduced. The settling time decreased to 4.24 s when the OMB-PSS4B is used. Moreover, there is a small reduction in the peak power angle with the utilization of OMB-PSS4B.
This paper presents a refined finite-state predictive torque control (FS-PTC) for two-level Voltage Source Inverter (2L-VSI) of induction motor (IM) by introducing a specific voltage vector selection lookup table to the algorithm. The concept behind this method is to decrease the number of voltage vectors (VVs) instead of using seven voltage vectors (VVs) to test the cost function, resulting in a substantial reduction in the algorithm's analytical terms. MATLAB/Simulink is used to analyze the efficiency of the refined algorithm under torque dynamic condition (staircase speed reference). The results of the simulations indicate that the refined algorithms able to regulate torque performance but not the stator flux performance or the total harmonic distortion (THD) stator current. Nevertheless, by increasing the weighting factor, it could reduce the flux ripple and decrease the THD current.
The peer-to-peer (P2P) energy trading creates a platform for all microgrid users to exchange their energy surplus and demand without the presence of a centralized authority. With P2P, the dynamic electricity market between nodes will be developed, thus increasing the overall throughput of the microgrid. To ensure the energy transactions in local energy trading meet the highest level of integrity, the blockchain system is implemented. Appropriate classification and structuring the literature on viable designs for local energy trading can assist researchers in effectively developing their subsequent planning for the local energy market. This study reviews the current research related to market clearing methods for blockchain-based P2P energy trading for microgrid system. The focus is on the auction theory, constrained optimization, game theory and agent methods.
This paper presents an approach to combine an occupancy simulator and SCADA software for the simulation and visualization of occupancy-based energy consumption in a campus building. We used Winlog SCADA and the occupancy model generated by an Occupancy Simulator to simulate the energy consumption in a campus building. A program code provided by Code Builder in Winlog SCADA was utilized to read the file generated by Occupancy Simulator and then implement the energy-related algorithm. The simulation results were graphically displayed on the SCADA HMI. The simulation results showed that the proposed simulator can simulate and visualize an occupancy-based energy consumption model in a realistic display that is similar to the real-application energy monitoring when using the SCADA system. Furthermore, the proposed approach offers an efficient tool in the development of SCADA-based energy monitoring systems.
In0.53Ga0.47As III–V semiconductor material has attracted significant attention from thermophotovoltaic research community due to its excellent optical and electrical properties. Furthermore, a high crystal In0.53Ga0.47 As structure can be grown on a lattice-matched InP substrate, making it a suitable candidate for large-scale production. However, the predominant drawback of the cell is low conversion efficiency, and there is a lack of detailed analysis of the effect of waste heat temperatures on the cell performance. Therefore, this work aims to conduct a comprehensive analysis via optimizing the active junction and characterizing the In0.53Ga0.47 As TPV structure under different waste heat temperatures ranging from 800 to 2000 K. TCAD Silvaco software was used to simulate the output performance of the TPV cell. The simulation results were validated with the reported experimental results. Results show that the variation of base layer thicknesses significantly affect the cell performance, with a significant increase in efficiency from 6.98 to 18.2% at a radiation temperature of 1000 K, as the base thickness increased from 1 to 13 μm. For radiation's temperatures from 800 K to 2000 K, the efficiencies of the optimized TPV cells increased by more than 10% as compared to the reference structure. The results obtained from this study contribute to the understanding of the effects of various waste heat temperatures on the performance of In0.53Ga0.47 As TPV cell, as well as to provide useful guidelines to fabricate high-performance In0.53Ga0.47As TPV cell for various waste heat temperatures.
Recently the interest in renewable energy has been increased worldwide. Therefore, the microgrid is considered more efficient and flexibility to improve the economic and environmental conditions by integrating the traditional distributed energy resources using technology devices and information technology (IT). Blockchain is one of these technologies, which has attracted in microgrid applications to build a sustainable society. The blockchain concept can provides immutability of the transactions in the microgrid such as record the amount of power generation and verify the transaction between the generators and end-users. blockchain based smart contract can be used for audit or solving a transaction dispute between the producers and the users by strip the necessity to link with third parties. In this paper, we present a number of recent research works related with blockchain application in microgrid and the application of the blockchain to improve the transactive resilience in the microgrid using smart contract.
The promoted continuous-time (CT) sigma-delta $(\Sigma\Delta)$ modulator clocked at 128 MHz with a hybrid active-passive loop filter is presented. The promoted phase-locked loop organization consists of phase frequency detector (PFD), charge pump (CP), low-pass filter (LPF), switch $LC$-tank voltage-controlled oscillator with divided-by-8 divider is combined in continuous-time (CT) sigma-delta $(\Sigma\Delta)$ modulator for 2.4 GHz wireless controlled power applications. The promoted prototype of phase-locked loop was implemented in $tsmc\ 0.18\ \mu \mathrm{m}$ CMOS process.
The photovoltaic (PV) emulator (PVE) is a specialized power supply that generates the same output as the PV module. However, the conventional control strategy called the direct referencing method (DRM) used for the PVE has oscillation problem. The problem is caused by the dependency of the DRM on the external components to compute the operating point. This problem can be overcome if the operating point is computed internally. This paper proposed a control strategy that compute the operating point internally using the particle swarm optimization (PSO). The resistance comparison method is chosen to implement the PSO into the PVE. The proposed PVE is compared with the conventional PVE that uses the DRM control strategy. Both PVEs use the similar buck converter, proportional-integral controller, and single diode model for a fair comparison. The result shows that the proposed PVE has no lower oscillation and higher accuracy when compared to the conventional PVE.
The persistent energy problems facing developing nations can be addressed by investing in renewable energy sources and technologies as these RES, such as fuel cell, PV energy, wind energy, and biomass energy can provide the needed energy to overcome energy shortages in such nations. MLIs are commonly used for high power high/medium voltage applications as they are considered an advanced topology for power conversion. Studies are currently focusing on the design of “reduced switch MLI (RS MLI) topologies” to facilitate the production of high-quality output without using numerous numbers of switches. These RS MLI are currently emerging techniques for various reasons, such as cost reduction, optimal sizing, reduced volume, minimized losses, and high efficiency. This study presents the design and development of a Multilevel Inverter (MLI) structure with fewer switch count for PV application. The proposed inverter architecture comprises of an H-bridge unit that acts as the polarity generator and the level generating unit comprising independent voltage sources with switches and diodes. It combines the proposed inverter with a PV array through a DC-DC converter. The boost converter will improve the output voltage of the solar photovoltaic system to its maximum value using MPPT (P&O). The proposed inverter is designed and tested for structures of five, seven, and nine levels by using MATLAB/Simulink. Selected results are presented to verify the validation of the 5, 7, and 9 levels MLIs. As a result, the proposed system successfully managed to achieve 96 % efficiency.
An improved symmetrical MLI topology capable of producing nine-level output utilizing seven switches (10 IGBTs) has been proposed. The proposed fundamental unit uses three voltage sources of the same magnitude and two self-balancing capacitors. The main features are fewer semiconductor devices with less voltage stress across them and reduced total standing voltage. Moreover, a generalized cascaded structure to generate more levels has also been discussed. Circuit performance is evaluated under static and dynamic load conditions. Switches pulses are generated using the nearest level control switching technique to reduce the total harmonic distortion. Comparison with other similar topologies has been accomplished in the paper to show the advantages of the proposed topology. The analysis found that the topology uses minimum switches and has a Total standing voltage per unit (TSV pu ) value of 3.25, much lower than the compared topologies. Also, less component count and the symmetrical nature of the dc-sources make the proposed topology suitable for solar PV applications.
This paper presents a simulation study to examine the internal model control-based proportional-integral derivative (IMC-PID) controller's performance implemented to the active front end rectifier (AFE) with reference tracking and disturbance rejection capability. The controller has been designed to control current and voltage in the d-q frame by implementing the inner and outer loop controllers using standard IMC-PID-based design procedures in each loop. However, the outer voltage loop exhibits initial sluggishness during the transient response because it has a pole lying on the origin; therefore, an active damping gain kf has been introduced at the outer voltage loop's feedback path to improve the design algorithm. In addition, during the initial state, the value of the control response to a step unit obtained using the standard IMC-PID-based procedure is K/Km, which has caused the output signal to oscillate. Therefore, multiplying the proportional part (P) of the PID controller with Km, the control response to a step unit starts at gain K, the maximum initial charging current needed to charge the capacitor. Simulation results show the controller performs good reference tracking and disturbance rejection, low total current harmonic distortion (THDi), low total voltage harmonic distortion (THDv), high power factor, and have the capability of bidirectional power flow.
As a member of the Paris agreement, Malaysia is committed to transforming into a low-carbon society. The Malaysian government aims to reduce greenhouse gas emissions by 45% on 2030. The Malaysian government is promoting energy-efficient vehicles (EEV) including future electric vehicles (EV), and aims to have 100% of EEV on-road by 2030. With the implementation of EV policies in Malaysia, these policies will act as an agitator for the mass adoption of EVs in Malaysian usage. However, from the viewpoint of the power system, EVs are additional loads when connect to the power grid. The massive penetration of charging station (CS) load has negatively impacted the distribution system, especially on the power losses. Hence, this situation has led to the need for unifying rules for the distribution system to accommodate this additional charging demand. In this research, the mitigation proposed is to implement optimal placement and sizing of multiple capacitor banks (CBs) for medium and low voltage distribution network systems optimized using the metaheuristic technique. The distribution system, CS and CBs are modelled using MATLAB environment. The metaheuristic technique used is Lightning Search Algorithm (LSA) and Modified Lightning Search Algorithm (MLSA) due to effectiveness from past research. Based on the simulation result, the MLSA method will best minimize the power losses at the practical 69-bus radial distribution network system. The study has proven that the optimal placement and sizing of variable CBs could reduce power loss. Furthermore, the results demonstrate that the multiple of CBs can provide a superior solution compared to a single CB. Hence, it concluded that the multiple CBs with the assistance of the MLSA method are the most suitable to be implemented in reducing power losses in distribution systems due to the massive penetration of EVs load.
New method for estimating state of health of lead-acid batteries is reported in the paper. The method is based on estimating Ampere hour capacity of the lead-acid battery. Lead-acid batteries are used by electric rickshaws prevalent in developing countries including India, Bangladesh and Indonesia. Replacing lead-acid batteries causes a huge dent in the savings of the electric rickshaws driver. For extending the life of lead-acid batteries it is necessary to know it's state of health first. The proposed method can be easily appended onto a battery charger.
We present the design of a half-bridge converter for a capacitively coupled wireless power transfer system. The load signal acts as a positive feedback signal for a self-oscillation circuit which generates the driving gate signals for the converter. Our research reveals a robust wireless operation for a large range of load resistors and coupling capacitors. Based on an electric network analysis we obtain design criteria for self-oscillation and for the power transfer. The theoretical predictions are confirmed by circuit simulation and measurement results on a converter prototype with GaN-HEMTs. We report on a transfer efficiency of 92% for a power greater than 50W at a switching frequency of 300kHz and 200V DC link voltage.
