Cost-Effective Control Algorithm for Extending Capacitor Lifespan

Opportunity

Electrolytic capacitors, widely used in energy storage systems (ESSs), photovoltaic (PV) systems and other power electronics applications, are prone to failure due to temperature sensitivity caused by high-frequency ripple currents. The degradation of these capacitors limits system lifespan, increasing maintenance costs and reducing overall efficiency. 

In PV systems, where reliable and low-maintenance power electronics solutions are critical, extending capacitor lifespan can significantly improve the uptime and operational efficiency. As global investments in solar energy continue to rise, energy storage solutions are also becoming essential. Similarly, the capacitor lifespan significantly affects the reliability of energy storage systems.  By reducing high-frequency ripple current stress on capacitors, this invention enhances system availability and longevity, reducing maintenance cycles and operational costs. 

This invention also extends to electric vehicle chargers and motor drives, where power electronics systems play a vital role in efficiency and performance. As power electronics technology expands across industries, integrating this algorithm can reduce warranty costs and improve long-term reliability. 

Technology

Electrolytic capacitors, commonly used in power electronics systems, degrade rapidly due to high-frequency ripple currents, which increase operating temperatures and shorten lifespan. A temperature rise of just 10°C can halve the capacitor lifespan, making ripple current reduction critical for long-term system reliability. 

This invention offers a software-based capacitor lifespan extension technology that optimises switching behaviour within the power electronics system, allowing high-frequency ripple currents to counterbalance rather than accumulate. By reducing high-frequency ripple currents without altering hardware, the approach provides a cost-effective capacitor control algorithm that seamlessly integrates into existing power electronics architectures. 

Figure 1(a) illustrates the power electronics system investigated in this invention. Experimental validation has demonstrated a 40% reduction in capacitor ripple current, significantly increasing the capacitor lifespan, as shown in Figure 1(b). The algorithm’s adaptability makes it applicable across PV systems, ESS applications, and other power electronic solutions, offering substantial benefits in reliability and cost savings. 

Applications & Advantages

Applications: 

• Energy storage and PV system optimisation for improved reliability. 
• Power electronics solutions with enhanced capacitor lifespan. 
• Electric vehicle chargers and motor drives for long-term performance. 
• Capacitor high-frequency ripple current reduction. 

Advantages: 

• Extends capacitor lifespan by reducing high-frequency ripple currents. 
• Enhances power electronics system reliability without hardware modifications. 
• Cost-effective capacitor control algorithm for seamless integration into existing architectures. 
• Applicable to multiple power electronics systems, including PV, ESS and EV applications.