Project

# Title Team Members TA Documents Sponsor
30 High-renewable microgrid for Railway Power Conditioner(RPC)
 Jiakai Lin
Jiebang Xia
Kai Zhang
Yongcan Wang
 Yi Wang design_document4.pdf
final_paper5.pdf
proposal2.pdf
 Lin Qiu
# Team Members:
- Yongcan Wang (Yongcan2)
- Jiebang Xia (jiebang2)
- Kai Zhang (kaiz5)
- Jiakai Lin (jiakail2)

# Problem:
In real life, the external power supply system is in three-phase while the traction network of an electrified railway usually only involves two phases Vdd and GND. If we randomly select two phases out of the three-phase power grid, there will be a mismatch in the power consumption for each power line. We need to come up with an idea to balance the power consumption on each power line.

During the operation of electrified railways, the environment is not stable and small disturbances may exert on the system, which requires our system to have resilience in eliminating those disturbances. For example, the friction between the train and the ground varies in different areas and the train may climb up a ramp sometimes. In order to make the train operate at a uniform velocity, we cannot simply exert unified traction. It's also impossible for the power supply voltage to remain the same and there must exist some small vibration. It's vital to make the train function properly invariant with the outside environment.

# Solution overview:
The overall plan is to connect the three phases of the power grid circularly to the traction network at different sections of the railway. In other words, suppose the three phases are phase a, b, and c and we choose phase (a, b), phase (b, c), and phase (c, a) as input voltage periodically every few kilometers, the power supply grid will be close to balance in the large scale.

To balance the power supply on the breakpoint of the traction network where the selected three phases input is changed, a Railway Power Conditioner (RPC, hub of power conversion) is designed to dynamically balance the interphase active power.

A microgrid is also connected to the RPC and plays the role of a reservoir. It will absorb extra power or supply backup power during disruption, and it provides an approach to utilize regenerative braking energy to increase energy efficiency.

Control theorems are added to make the traction network stable and improve the quality of the power supply.

# Solution component:
## 1. Railway Power Conditioner (RPC):
This is the main subsystem of this project. It aims to dynamically balance the inter-phase active power, independently compensate the reactive power of each feeder and suppress its harmonics. We will use converters, AC/DC transformers, and RC filters in this subsystem. Transformers are used to step down the high voltage at the traction network to a relatively safe low voltage to handle. AC/DC converters are used to eliminate the phase difference at the two sides of the breakpoint and make it possible to connect them. RC filters are used to suppress harmonics and provide a stable DC voltage.
## 2. Control system:
It's the algorithm part of the project. We will use control theorems to make the train run in a safe and stable manner. We will start with open-loop control, and we will design PID closed-loop control later. We will also try data-driven maximum power point tracking control to extract maximum power from the solar panel. Through designing control signals for switching functions from Arduino, some switches can be opened or closed to achieve the purpose of those converters.
## 3. MTDC (Multi-terminal dc transmission control system:
This is the bus that connects RPC and other sources from the microgrid (like photovoltaic, battery, and even wind power). We need to design an MTDC that can satisfy our different expectations. For RPC and battery, we need a stable voltage reference, while for solar panels, we need to change the DC voltage value to extract maximum power. This can be realized by designing a proper DC/DC converter for each component.
## 4. Three-phase voltage source and solar panel:
These are the external voltage sources that provide power to the system. Instead of using the 110kV/220kV external power grid, we will use a much safer 220V three-phase voltage source from sockets. We will borrow solar panels from the lab and connect them in parallel as the microgrid source to simulate the solar farm.

# Criterion for success:
- Two AC voltage sources with different phases are converted into the same DC voltage through RPC. This implies the two voltages on either side of the breakpoint are connected and this proves the functionality of RPC.
- MTDC provides the required voltage for each connected component. We can use a voltmeter to test whether the voltage is the desired voltage for each port of the MTDC. The port for RPC and the battery should be stable, while the port for the solar panel should vary with time to meet the maximum power extraction.
- Apply some disturbance on the system to assess its stability. We can connect a resistance in series with the train load to simulate that more traction is needed. If the DC voltage at RPC becomes stable again soon after we add the resistance, the system has relatively good resilience. In addition, the advantages and disadvantages can also be judged by comparing the results of different algorithms, such as whether the maximum power point tracking can be achieved in the shortest possible time.

# Distribution of work:
1. One group member (EE *Yongcan Wang*) will do some research on designing the voltage level for each wire of the system. He is also responsible for selecting the appropriate transformers that meet these voltage specs on the market and installing them into the circuit.
2. One group member (EE *Jiebang Xia*) is responsible for the converters and filters part. He needs to think about how to use appropriate semiconductor components to build the AC/DC and DC/DC converters to meet our requirements for RPC and MTDC. He is also responsible to select the specification of the filter that results in desired time constant.
3. One group member (EE *Kai Zhang*) is responsible for clarification of the whole principle. This member needs to understand the working principle of the whole system and will also help the member who is responsible for hardware, help him with some connections, select hardware specifications, etc.
4. One team member (ECE *Jiakai Lin*) is responsible for the programming part of the software, especially designing the control algorithms for those AC/DC and DC/DC converters in different areas and the short-time maximum power point tracking algorithm.

Our project has some control programs that need to be completed by ECE students, and most of the other parts are the study and practical application of some hardware principles of electrical engineering, as well as the application of power supply and power grid knowledge.

Cloud-controlled quadcopter

Featured Project

Idea:

To build a GPS-assisted, cloud-controlled quadcopter, for consumer-friendly aerial photography.

Design/Build:

We will be building a quad from the frame up. The four motors will each have electronic speed controllers,to balance and handle control inputs received from an 8-bit microcontroller(AP),required for its flight. The firmware will be tweaked slightly to allow flight modes that our project specifically requires. A companion computer such as the Erle Brain will be connected to the AP and to the cloud(EC2). We will build a codebase for the flight controller to navigate the quad. This would involve sending messages as per the MAVLink spec for sUAS between the companion computer and the AP to poll sensor data , voltage information , etc. The companion computer will also talk to the cloud via a UDP port to receive requests and process them via our code. Users make requests for media capture via a phone app that talks to the cloud via an internet connection.

Why is it worth doing:

There is currently no consumer-friendly solution that provides or lets anyone capture aerial photographs of them/their family/a nearby event via a simple tap on a phone. In fact, present day off-the-shelf alternatives offer relatively expensive solutions that require owning and carrying bulky equipment such as the quads/remotes. Our idea allows for safe and responsible use of drones as our proposed solution is autonomous, has several safety features, is context aware(terrain information , no fly zones , NOTAMs , etc.) and integrates with the federal airspace seamlessly.

End Product:

Quads that are ready for the connected world and are capable to fly autonomously, from the user standpoint, and can perform maneuvers safely with a very simplistic UI for the common user. Specifically, quads which are deployed on user's demand, without the hassle of ownership.

Similar products and comparison:

Current solutions include RTF (ready to fly) quads such as the DJI Phantom and the Kickstarter project, Lily,that are heavily user-dependent or user-centric.The Phantom requires you to carry a bulky remote with multiple antennas. Moreover,the flight radius could be reduced by interference from nearby conditions.Lily requires the user to carry a tracking device on them. You can not have Lily shoot a subject that is not you. Lily can have a maximum altitude of 15 m above you and that is below the tree line,prone to crashes.

Our solution differs in several ways.Our solution intends to be location and/or event-centric. We propose that the users need not own quads and user can capture a moment with a phone.As long as any of the users are in the service area and the weather conditions are permissible, safety and knowledge of controlling the quad are all abstracted. The only question left to the user is what should be in the picture at a given time.