How can modular multilevel converters (MMCs) enhance the performance and reliability of smart transformers?

2 How do MMCs work in smart transformers?

Smart transformers can use MMCs as their core component to convert the input AC voltage to a DC voltage, and then to an output AC voltage with a different magnitude and frequency. The input and output sides of the smart transformer are connected by a DC link that can also store or exchange energy with other sources or loads. By regulating the DC link voltage and the output voltage, the smart transformer can perform various functions, such as voltage regulation, power quality improvement, frequency conversion, and power flow control.

3 What are the benefits of MMCs for smart transformers?

One of the main benefits of MMCs for smart transformers is their high efficiency and low losses. Since MMCs use capacitors instead of inductors or transformers, they have less magnetic losses and less reactive power consumption. Moreover, MMCs can operate at lower switching frequencies than other converters, which reduces the switching losses and the stress on the devices. Another benefit of MMCs for smart transformers is their high reliability and fault tolerance. Since MMCs are composed of many submodules, they can tolerate the failure of some submodules without affecting the output voltage or current. Furthermore, MMCs can isolate faults and bypass faulty submodules by using redundant or spare submodules.

4 What are the challenges of MMCs for smart transformers?

Despite their advantages, MMCs also face some challenges when used for smart transformers. One of the main challenges is the capacitor voltage balancing. Since each submodule has its own capacitor, the voltage across each capacitor must be balanced to ensure a uniform output voltage and avoid overvoltage or undervoltage. This requires a sophisticated control strategy that can monitor and adjust the capacitor voltages in real time. Another challenge is the thermal management. Due to the large number of submodules and devices, MMCs generate a significant amount of heat that must be dissipated to avoid overheating and degradation. This requires a proper cooling system that can handle the thermal stress and maintain a safe operating temperature.

5 What are the future prospects of MMCs for smart transformers?

MMCs have demonstrated remarkable potential for smart transformers, yet there is still room for improvement and innovation. Future prospects of MMCs for smart transformers include creating new submodule designs and configurations to reduce the number of components, increase power density, and enhance performance. Additionally, integrating new materials and devices, such as wide-bandgap semiconductors, supercapacitors, and magnetic materials may increase efficiency, reliability, and durability. Finally, advanced control and communication methods, such as artificial intelligence, machine learning, and internet of things can optimize the operation, coordination, and protection of MMCs and smart transformers.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?