Profile:
A part of the Chair of Mechatronics and Electrical Drive Systems at the Rhineland-Palatinate Technical University of Kaiserslautern-Landau is dedicated to the research and development of electrical drives as well as the hardware and software development of power electronics for a wide range of applications. These include battery systems, electrical power grids and drives.
Key Areas of Expertise:
Intelligent and Modular Energy Storage and Converter Systems:
A central research focus of the Chair of Electric Drive Systems and Mechatronics is the design of modular battery storage systems based on modular multilevel converter (MMC) technology. These systems offer high flexibility and efficiency when integrated into various applications such as solar power plants and electric vehicles. Through the close integration of software and hardware developments, innovative approaches to the control, monitoring and optimisation of energy storage and converter technology are being researched in order to create sustainable and efficient energy systems.
Electrical Drive Systems:
There are currently around 8 billion electric drives in use in the European Union, accounting for almost half of electricity consumption. The electric drive industry is very diverse and covers a wide range of technologies, applications and sizes, from small cooling fans for computers to large drives for heavy industry. The Chair of Mechatronics and Electric Drive Systems has a strong research group and experts working on improving the performance of electric drives in various applications such as electric vehicles, industrial automation, renewable energy integration and household and consumer appliances. This goal can be achieved by reducing power losses, minimising drive noise that can cause discomfort in residential areas, including lifts and electric vehicles, and improving motor efficiency and performance.
Enhancing Energy Resilience for Future 6G Networks:
In light of recent natural disasters and cyber security breaches, it has become clear that energy infrastructure, particularly on the supply side, remains highly vulnerable to disruption. The advent of 6G technology will be no exception to these vulnerabilities. The Chair of Mechatronics and Electrical Drive Systems at RPTU is committed to strengthening the resilience of our energy supply system with its extensive and long-standing experience in the development and operation of power electronic devices. This includes strengthening power electronic components against cyber-attacks and ensuring their robustness against natural disasters.
To achieve this goal, the department has outlined a number of sub-projects that are being actively pursued under its leadership. These sub-projects include the following initiatives:
1. Improving battery monitoring methods:
Improve battery monitoring methods, including parameter assessment and age estimation as well as fault diagnosis, to improve the monitoring and management of power supply within the 6G network.
2. Cloud-based monitoring and optimal control of reconfigurable energy storage in base stations:
Implementation of cloud-based monitoring systems for efficient and optimal control of reconfigurable energy storage systems in base stations to ensure an agile and responsive energy infrastructure.
3. Protecting the 6G infrastructure from cyber threats:
Conduct extensive research on potential cyber threats targeting energy management systems and power electronics devices within the future 6G supply chain. Develop robust and resilient solutions to ensure their uninterrupted operation.
Voltage and Power Flow Regulation in Electrical Networks:
The Chair of Mechatronics and Electrical Drive Systems has extensive expertise in voltage and power flow control in electrical distribution networks. A particular focus is on the integration and size reduction of controllers. The research group investigates power flow controllers for both AC and DC networks. Their research activities cover both the hardware and software aspects of power flow controllers. In addition to their primary function as controllers, additional functionalities such as harmonic compensation and filtering, balancing asymmetries in the network, and controller behavior in fault conditions are also examined. The research and development efforts are supported by laboratory facilities as well as a wide range of testing and simulation tools.
Why do we need power flow controllers?
Increasing electrification as part of the energy transition has led to an increasing load on low-voltage grids. This is partly due to the growing number of photovoltaic systems, electric vehicle charging stations and other electrical consumers and generators. These changes lead to a strongly fluctuating grid voltage that can exceed both the lower limits and the upper limits of the permissible voltage ranges, as specified in the DIN EN 50160 standard (±10% of the nominal grid voltage).
Such grid problems arise primarily because generation and consumption often occur at the same time, but at different intensities. While the feed-in from PV systems increases the voltage, consumers such as charging stations reduce the voltage. This leads to a volatile voltage profile that is a risk to grid stability and can cause local overloads. Figure 1 shows such a case.
Established solutions and their limits:
Conventional grid expansion:
The replacement or reinforcement of operating equipment such as transformers or lines can increase load capacity and voltage stability, but is often associated with high costs, time-consuming construction work and disruption for local residents.
Controllable local grid transformers (rONTs):
These transformers can regulate the voltage by adjusting the transformation ratio. However, they are not suitable for controlling current flows or limiting thermal loads.
Voltage and string regulators:
These devices can be used flexibly in the grid to regulate voltages, but without direct control of the current flow / power flow.
Reactive power management:
Compensation of reactive power by decentralised generation plants is already applied, but this is not sufficient.
Grid topology changes:
Switching from radial (typical design of low-voltage grids, due to easy-to-implement grid protection) to meshed grid structures can increase grid capacity and improve the voltage band, but is limited in its effectiveness by the inhomogeneity of the grid load. See Figure 2.
Line 1 is overloaded with a current of 220 A (typical current values in low voltage go up to approx. 200 A) while line 2 would still have capacity. This is exactly where the concept of power flow controllers comes in.
How does a power flow controller work?
To explain the operating principle, Figure 3 shows a controllable voltage source, which represents a power flow controller, integrated into a line section with the impedance ZAB between nodes B and C, which have the voltages UB and UC, respectively . The voltage source generates an additional voltage U+ that is adjustable in magnitude and phase (angle ϑ). The impressed additional voltage U+ causes an additional current I+ that is added to the existing line currents IAB and IAC according to the superposition principle. This leads to a targeted redistribution of the power flows within the grid.
Figure 4 shows the grid situation from Figure 2 with a power flow controller (PFC).
High-Current Connections for Power Electronics:
The chair not only has expertise in the design and development of printed circuit boards for power electronics, but also in the mechanical connections required to achieve this power supply. Our expertise lies in the complete design and development of printed circuit boards for power electronics through to the simulation and testing of the assembled mechanical connection. The chair has access to simulation software such as Ansys Workbench as well as other packages such as Maxwell, Fluent and Motor CAD. For testing, the laboratory is equipped with power supply units that can deliver up to 1200 A of current.