Research Projects

1) MOBILE SPEED CHARGING FOR EV WITH ENERGY STORAGE

Electric Vehicle (EV) will dominate land transportation in the future. As known, the EV is driven from electric source that has been stored in EV battery. Imagine in the future, there will thousands of charging stations that are in placed around the electric grid/road especially on highway or at fleet stationary station which require who has faster charging process will win the competition. Therefore, it requires a set of charging station with the appropriate faster charging time vs distance calculation before the next cycle of charging with high storage mobile power also that can be move form one place to another place. Currently, there are 3 levels of stationary charging station which depend on the time and power of charging. Therfore, this project is to propose to have a Mobile Speed Charging with Smart Battery Storage for DC fast charging or AC fast charging. It is where 240V input supply for 100A with 90% state of charge efficeiency for energy storage charging are needed for mobility proposes which can be provided by the energy storage such as battery. This charging station modules will be a combination of two power converters which are multilevel inverter for normal AC charging system with fast charging time based power electronocis compenets using GAn semiconductor module while the multilevel DC converter for ultra fast charging will also been integraed on this mobile system will used an highly discharging battery which capble to generate high current at the output with short time of period. This battery and UFC will be integrated with Intellignet microcontroller feasibiliy and decision in order to control, monitoring and integrate the discharging mode of the battery based on time and distance needed by the EV.

Normally it between 120 minutes to 30 minutes charging for 200kM distance based on types of internal EV configuration and battery rating. However this UFC system can be developed in the modular circuits such as a lego set mechanism. It is where the UFC can be implemented with normal AC grid or integrated with the Renewable Energy sources without modification on the converter curcuit because it has been based on multilevel structure that use GAs components which has high power rating that allowed high current to flows within short time. Meanwhile for DC-UFC it also can be developed using the same DC converter that generate 120kW power output for 300A.The most chalenging of both UFCs is the battery management system which required fast response, fast switching and intelligent battery monitoring during discharging but during charging it can be based on normal battery charging. It mens the microcontroller or the brain of the selection of mode is very improtant.

Thefore, the control strategies based on intelligent based decision, should be adopted when the numbers of the converters/charging time are increased which due to a new unknown parameters for the controller design. Therefore, for the fast charging mechanism at UFC, required the rated power decision in order to fullfill the condition of high power flows. The battery management is mainly on the monitoring sytem where it is also important due to types of the battery, life cycle and also the SOC status of the battery in order to avoid deplection on the battery performance.

The solutionn for fast charging, can be categorized into active or passive configurations systems. The meaning of active is when the charging station is been developed with the brain and strengh meanwhile for the passive, is a circuit with only strengh and without an accurate design components especially the converter circuits. However, both configurations can increase the charging speed depanding on how the system strategies/configuration have been applied to the charging station which follows the international standard for mobile station EV charging. The proposed active stucture give an advantage and it need a knowledge on a new control system that determined the robustness and the fastness of the dicharging and also able to support the needs of State of Charge (SOC) of the battery due to high requested current with short period of time that can be proportional to the distance to be traveled. As for the strengh circuit, it required an extra circuit configuration such as multilevel sturcture where can be form of AC input or DC input strategies as charging station that been used the market but combine with energy storage is something new here. Therefore, the suggested system will be a combination of brain and strengh as for Mobile UFC charging where at the end it can be applied at various types of the EV where this will be known as Level 3+ EV charger. Therefore, this project is planned to develope a fully mobile UFC using local talent and product t which can contribuite to knowledge, human capital and at the end as a revenew profit for the sponsor.

2) Title : Robust and Deep Learning Control for Multilevel Inverter D-STATCOM for New Distributed Generation Sources to the Existing Local Grid

Multilevel inverter will be a converter for the next Distributed Generation structure. It is because it only required a small amount of DC input but generating high AC voltage source at the output. At the same time, by the advancement of the controller theory the control structure can be robust and efficiently in any conditions. Therefore, this project has taken a first step to applying robust with deep learning construction to the multilevel inverter for D-STATCOM or Dynamic Voltage Restorer (DVR) configuration. The D-SATCOM and DVR will be modeled in PSCAD with IEEE 9 busbar or TNB Johor Bahru mesh circuit. By develop this real network, and also by introducing the fault system it will help the authority to determine the best location and configuration for multilevel D-STATCOM. This location and restoration are very important to create a fast response mitigation on voltage and frequency while at the same time reduce the THD from the injected current. This controller will also respond to any disturbance form the fault and grid with the deep learning analysis based on Fuzzy Logic or Neural Netwoks which able to communicate between several outsource data from the D-STATCOM/DVR. Therefore, the increasing the number of inverter level output, the size of the low pass filter can be reduced which it will contribute for better connection between the DG to the electrical grid. All the results show that multilevel D-STATCOM/DVR inverter is very useful as the alternative equipment when new DG connection that needs to be installed with the existing complex mesh network to contribute on high power, high grid accuracy and high respond of the controller stability.

3) Grid Stability Improvement for Electric Vehicles Charging Station in Fast Charging Battery

The number of electric vehicles (EVs) is increasing tremendously since the last decade. This is due to the technology advancement especially in electric motor design and government policy in order to reduce the amount of carbon foot print in the atmosphere generates from the vehicles. As the result, the United Kingdom will impose totally an Electric Vehicles (EVs) in their transportation network in 2040. All of these arguments have shown that, EV will be the dominant discussion very soon in time. However, most of the aspects on the EV such as the charging/discharging of battery, energy management between the battery and the driving motor or vice versa, the concepts of Vehicle to Grid (V2G) or Grid to Vehicle (G2V) are well been discussed by the researchers around the world, but there is less explanation regarding to the charging station issues.

As known, the EV charging station consists of power converters configuration. It is connected to the existing electrical grid with the power converter such as the rectifier in order to convert the AC grid input to DC output voltage source. When the EV is connected to this charging station, the behavior of the charging station will be changed. Therefore, the EV will see the power converter as a nonlinear source. At the meantime, the EV battery is actively contributed to the frequency pollution in grid stability when it has been connected to the converter. As a result, the autonomous grid between EV loads to the grid source cannot be performed. In this case, if the grid stability is been disturbed continuously, the power flows between the grid to the battery cannot be maintained in order to give fast charging period to the EV. This problem is not happen to the power flows only, but also it will reduce the power factor and grid frequency at the AC source in order to have continuous primary frequency control at the grid side. As for seen from the EV perspective, the ability to give high respond on the state of charge (SOC) of the battery is also important by considering of the effect of harmonics line impedance to the EV battery-grid connection also need to be discussed. The EV battery is changing rapidly when the capacitance mode occurs during charging while it is in inductive mode during discharging will also contribute to the AC grid stability.

As for an example, one EV will not contribute to those problems but what happen when hundreds of EVs are connected to the same AC-Point of Common Coupling (PCC) of the power converter. Here, it will create tremendous problem if these issues are not been tackled at the beginning. Therefore, it is necessary to make sure, the EV charger is able to minimize the impact to the electric grid by providing high power factor in order to make sure the EV battery can be charged at the very short at time while maintaining the frequency grid when the energy flows to the battery regarding to the SOC of the battery.

In order to solve the problems stated above, several researchers have used a two stage power converters or two stage controllers. The two stages power converters are by combining the AC/DC converter (rectifier) with a DC/DC converter before connects to the EV. This strategy will increase the number of switches in the power converters and will also contribute to the total cost of EV charger itself. At the meantime, this configuration needs a dual loop controllers at the rectifier whereby, first it needs to maintain the DC link voltage at the DC/DC converter from the outer voltage loop control while at the same time it also needs to have a power flows control as a inner loop control to maintain the stability at the AC grid. Another problem is on the battery charging period and the SOC condition of the battery during charging that will not be overcharge that will short the lifetime of the battery.

In this project, its proposes to use only one power converter which is the AC/DC converter in order reduce the number of switches and also to combine the voltage output control or direct power control as the rectifier controller. From this figure, the idea is to implement the synchronous motor formulation in rectifier control. As known, the synchronous motor will maintain the AC grid input by giving the sinusoidal signals to the voltage and current while maintaining the AC frequency. At the meantime, the torque generates from the motor is respond to the changes of the power flows from the AC source and can be behave as a DC source as when it been applied to the EV battery. This concept has been applied to the rectifier with constant load where it shows that, the rectifier is able to give high power factor at the AC source and at the same time able to control the DC voltage. However, some modification is necessary in order to use this concepts of fast charging at the EV battery whereby it has two modes which are constant current charge and constant voltage charge conditions.

4) The Decentralized Control Structure for Democratically Distributed Generations in an Electric Distribution System

This project emphases on improving democratic power sharing at AC distribution system for decentralized parallel connected inverters in the microgrid. The effect of grid line impedance and feedback circulating current on power flow in AC system are presented. A detailed AC power flow analysis for parallel connected DG inverters which influences on the modern democratic structure will be investigated. Therefore, numerous active and reactive power schemes were attained to envisage the influence of voltage power angle and amplitude during power flowing in the electric system at different voltage levels. Another issue in parallel connected inverters is due to circulating current. This is a serious issue that must be addressed when parallel DG inverters are been applied in a microgrid. This current is used as a tool to define an imbalance between inverter and can be present irrespective of the load and electrical grid. At low rated load or a no-load condition, circulating current can be a source of power exchange between the inverters. This can affect the whole control operation of the system and may cause damage to the inverter. During high load, there will be no net power flow among inverters that will make the DGs power unbalance. However, it produces extra power losses in line impedances at the same time.

Practically , when the rating of an inverter is different, such as like; Dg1 = 2Dg2, the level of current supply also it'll be different is there's no control mechanism for the voltage output. In such cases, the current from Dg1 will be double that of Dg2 and increase the circulation current effect. So, if there is no, net democratic active or reactive power flow between inverters, the negative influence current is the extra line impedance losses. Each parallel connected inverter has an output voltage that also needs to have the same frequency , amplitude and phase in an ideal case with the electrical system but it will deviate when there is a circulating current flowing to the inverter. An improved instantaneous average current sharing scheme with two additional gain schedulers is proposed here to improve conventional controller performance underline impedance mismatch. The proposed model is used for voltage and current controller design. At the end, the power sharing scheme utilizing a decentralized controller for parallel connected inverters in microgrid will validate the power sharing schemes capability to reduce distribution power losses and improve voltage regulation.

5) Sensorless Dynamic Field Oriented Control in Induction Motor During On-Road Driving for Electric Vehicle

Electric Vehicles (EV) will be the main transportation in the future. It is because, it has friendly environment affects, able to generate reverse energy for feed-in tariff mechanism and also able to reduce mechanical configuration in conventional car. These advantages have attracted more research on this new technology. During motoring of an EV, speed and torque sensors are the main parameter inputs that will determine the speed, stability, precision and power flow management inside the EV. Therefore, these sensors should be in the healthy condition all over the time whatever the condition of the road.

Currently, speed and torque sensors are used to regulate the performance inside the EV in order to give a good dynamic response especially for the torque and speed. However, the price for those sensors is relatively high and very sensitive to the road condition. Therefore, this project is about to develop a sensorless dynamic Field Oriented Controller (FOC) for the Induction Motor (IM) during on-road driving. The new controller will be tested on the constant torque and varying torque in order to mimic the road condition. The biggest challenge is when; the EV is in motoring mode but it is on un-flat surface, where the dynamic of the motor will be changed frequently. Therefore, it is necessary for EV to give continuous regulated speed for maintaining the motor efficiency and battery level.

In order to develop this sensorless dynamic FOC control, a speed estimation behavior needs to be included which can represent as a speed sensor signal. This improved controller will be tested in Hardware in The Loop (HIL) model where it will mimic the behavior of the EV in real time condition. Therefore, by using this technique the time, accuracy and robustness or the controller can be measured in IM for verification.

6) Rapid Control Prototyping for Droop Control Strategy for Power Flow in Inverter-Grid Connection

This project is to develop a single phase inverter grid connection using Texas Instruments microcontroller with Rapid Control Prototyping process application. For this project a single phase inverter hardware with dc input will be used for the system development. As for the power flows process voltage and current sensors will be used at the feedback control with the droop controller process where will be build in the TI using the MATLAB-Simulink Software. At the same time the power flow control should be developed in order to have a good power distribution among the inverter to the grid.

7) Hardware in the Loop for D-STACOM during Voltage Sag Mitigation on the Renewable Distribution Gird

This project is to develop the D-STATCOM in order to solve the voltage sag problem at the distribution grid. The distribution grid will create a faulty condition which can lower the voltage at the distribution line. Therefore the D-STATCOM will be used to inject the necessary voltage to mitigate the voltage fault. This project required student to develop the Hardware in the Loop process using the low cost microcontroller. The microcontrollers will be behave as the medium of interfacing between the process flows and the real time applications. it also require the student to construct the system consist of two renewable energy sources with the D-STATCOM connected at the common bus bar.