Solar Inverters
Aluminum Electrolytic Capacitor Solutions for String and Central Photovoltaic Inverters
Summary: HUAYU provides aluminum electrolytic capacitors for photovoltaic inverter applications. Long-life snap-in series (CD295, CD296) with 105°C rating are optimized for the 10-20 year service life requirements of solar inverters.
Key Capacitor Requirements
Wide Temperature Range
Must operate reliably from −25°C to +85°C with daily thermal cycling. Electrolyte must remain stable without freezing or excessive evaporation over thousands of cycles.
10+ Year Field Life
Solar inverters are expected to operate for 10–15 years without maintenance. Capacitor life must be calculated at actual operating temperature, not just rated temperature.
Low ESR at High Frequency
Modern solar inverters switch at 16–50 kHz. Low ESR at these frequencies reduces internal heating and improves inverter efficiency.
Moisture Resistance
Outdoor installations expose capacitors to high humidity and condensation. Robust seal design prevents moisture ingress that accelerates electrolyte degradation.
Capacitor Functions in Solar Inverters
DC-Link Buffer
Smooths the rectified PV input and provides energy storage for the MPPT stage. This is the largest capacitor in the inverter and the most critical for reliability.
Output Filtering
Filters high-frequency switching harmonics from the inverter output before the grid connection. Lower capacitance values but high ripple current requirements.
PFC Circuit
Active PFC boost circuits require low-ESR capacitors to achieve high power factor and comply with grid harmonic standards (IEEE 519, IEC 61000).
Recommended Series
HUAYU series best suited for solar inverter applications
| Series | Type | Key Features | Typical Application |
|---|---|---|---|
| CD298 | Snap-In | 10,000h life, wide temp range, high ripple | String inverter DC-link |
| CD294 | Snap-In | Ultra-low ESR, extended life | Micro-inverter, output filter |
| CD13HL | Screw Terminal | 105°C, 10,000h+ life | Central inverter DC-link |
| CD17FX | Snap-In | Miniature, high reliability | Small string inverter, micro-inverter |