How the power conversion system and battery management system work in tandem for more efficient energy consumption.

Recently, I came across a report that highlighted the energy price inflation rate by commodity in the European Union, which for January 2023 was measured at a staggering 20.6%. This figure was in stark contrast to the inflation rate recorded in January 2019, which was a mere 2.4%. It made me reflect on the challenges we’ve faced in the past year with the rising energy demand and subsequent surge in electricity bills. It has affected all of us in various ways and heightened our awareness of global energy consumption and the need for solutions. Renewable energy, particularly energy storage systems, has been on the forefront of my mind, as it offers innovative and sustainable solutions to address the growing energy needs. In this blog post, I will delve into how energy storage systems work and the benefits they offer as a sustainable energy solution. So, let’s jump right in!

Energy storage systems are made up of two main functional blocks that work together: the power conversion system (PCS) and the battery management system (BMS). The PCS and BMS work in tandem to form an ESS, catering to different use cases depending on location and requirements. Figure 1 below illustrates the energy supply chain before-the-meter that is the generation and transmission, and the consumption which is the behind-the-meter stage. However, for the purpose of this blog, I will specifically focus on the behind-the-meter segment, where the functional blocks are also present.

Fig. 1: Energy supply chain.

Power conversion system

The power conversion system (PCS) plays a crucial role in energy storage systems by facilitating in the efficient conversion of power from one form to another. For instance, when using renewable energy sources like solar panels on a residential building, the generated power is in DC form, which needs to be converted to AC power before it can be used by electrical appliances. Energy storage systems (ESS) that are typically used in conjunction with photovoltaic (PV) installations, which are expected to be used increasingly in the future, can be categorized into two main coupling topologies: AC coupled systems and DC coupled systems. DC coupled installations, also known as hybrid inverter installations, are commonly used in residential setups. The system typically consists of PV panels, a maximum power point tracking (MPPT) DC/DC stage, a bidirectional DC/DC stage for battery connection, and a single inverter stage for both battery and PV panel. One of the key benefits of this system is its increased efficiency, as it eliminates one power conversion stage, resulting in higher overall performance. Additionally, it is more cost-effective as it requires fewer semiconductor components, leading to reduced costs. The specific topology of the system may vary depending on factors such as whether it is a single or three-phase system, as well as the battery voltage, which may necessitate MOSFETs and Gate Drivers in the power range of 60 V to 1200 V.

Battery management system

The battery management system (BMS) is a crucial component of energy storage systems responsible for cell charging, balancing, and state of health monitoring. I’d say that the function of BMS could be compared to the human body’s metabolism. The BMS, like the metabolism, constantly monitors the state of the battery cells and adjusts the charging rate to ensure they remain healthy and balanced. Similarly, our metabolism constantly monitors the nutrients in our body and adjusts the uptake and utilization rate to ensure our body stays healthy and balanced. In both cases, it is essential to have a well-functioning system that can monitor and adjust the internal workings to maintain optimal performance and prevent damage or malfunction. Thus, BMS is essential for optimal performance and efficient utilization of energy storage systems.

Solutions for energy storage systems

Infineon is dedicated to providing solutions which promote a sustainable and greener future. In figure 2 below you can see Infineon’s solutions for energy storage systems. For power conversion systems, solutions below 30 kW are often better served with discrete components such as OptiMOS, CoolMOS, and CoolSiC MOSFETs, as well as CoolGaN for more advanced, fast switching designs. Alternatively, for commercial and utility-scale systems, a modular approach that employs discrete IGBTs is a suitable choice, depending on system configuration module solutions. Additionally, functionally integrated EiceDRIVER gate driver ICs,  XMC controllers and security solutions such as OPTIGA are ideal in a wide range of energy storage system designs, while StrongIRFET power MOSFET family is optimized for low RDS(on) and high current capability. Lastly, CoolSET is an optimal solution for auxiliary power supply while the digital isolators ISOFACE can be used within the control & connectivity functional block.

Fig. 2: Infineon’s solution for energy storage systems.

On a final note, energy storage systems are a key solution for the increasing demand for energy and the need for sustainability. By utilizing energy storage systems, we can promote efficient energy consumption and sustainable energy generation, which can help us achieve a greener future. As someone who is passionate about environmental sustainability, I’m excited about the potential of energy storage systems as a sustainable energy solution and I have to say that it’s encouraging to see companies like Infineon contributing to the development of energy storage systems, which can play a vital role in promoting efficient and sustainable energy consumption. It goes without saying that by using energy storage systems, we can help create a more sustainable future for ourselves and future generations.

This article is excerpted in：https://semiengineering.com/empowering-greener-future-role-of-energy-storage-systems/