Inverters
Aluminum Electrolytic Capacitor Solutions for General Inverter Applications
Summary: HUAYU offers capacitor solutions for general inverter applications including solar, wind, and industrial power inverters. Snap-in and screw terminal series handle DC-link smoothing, output filtering, and energy buffering with voltage ratings up to 500V.
Capacitor Roles in Inverters
DC-Link Smoothing
The primary function — smooths the rectified AC into stable DC. Must handle combined ripple from the rectifier (low frequency) and inverter (high frequency) stages simultaneously.
Output Filtering
Filters PWM switching harmonics from the inverter output to produce a clean sinusoidal waveform. Requires capacitors with low ESR at the PWM carrier frequency.
Snubber / Absorption
Absorbs voltage spikes during IGBT switching transitions. Small-value, low-inductance capacitors placed close to the switching devices.
Key Selection Factors
Voltage Derating
Operate at 70–80% of rated voltage for maximum life. For a 540V DC bus, use 600V rated capacitors or series-connect two 400V units with balancing resistors.
Thermal Management
Internal heating from ripple current is the primary life-limiting factor. Ensure adequate airflow and consider heat sink mounting for screw terminal capacitors in enclosed designs.
Ripple Current Calculation
Total RMS ripple is the vector sum of rectifier and inverter ripple components. Always apply a frequency correction factor when ripple contains harmonics above 120 Hz.
Mounting Considerations
Snap-in terminals for PCB mounting in low-to-medium power designs. Screw terminals for busbar mounting in high-power designs where vibration resistance and easy maintenance are priorities.
Recommended Series
HUAYU series best suited for general inverter applications
| Series | Type | Key Features | Typical Application |
|---|---|---|---|
| CD294 | Snap-In | Ultra-low ESR, extended life | Low-medium power inverter DC-link |
| CD297 | Snap-In | Load-life optimized, high ripple | Medium power inverter, PFC stage |
| CD17FX | Snap-In | Miniature, high reliability | Compact inverter output filter |
| CD13N | Screw Terminal | Optimized ESR, wide range | High-power inverter DC-link |
| CD13HL | Screw Terminal | 105°C, long life | Heavy-duty inverter, industrial drive |