Power Film Capacitors

Main features

Operating Temperature range [℃]	-40 to +85 (up to 105 for some models)
Operating voltage [V.DC]	450 to 2200
Capacitance range [µF]	1 to 5000
Major applications	Wind & solar power inverters, other inverters, chopper control and charge-discharge, high voltage/current power supplies

What quality standards do these capacitors meet?

AIC Tech's Power Film Capacitors meet several stringent quality standards to ensure high reliability and performance. They comply with the RoHS directive, which restricts the use of hazardous substances in electrical and electronic equipment. Additionally, the capacitors undergo rigorous testing in accordance with industry standards such as IEC60068-2-6 for vibration and shock resistance.

Can these capacitors be customized for specific applications?

Yes, AIC Tech offers customization options for their Power Film Capacitors to meet specific application requirements. Customers can request capacitors with specific electrical characteristics, such as different capacitance values, voltage ratings, and thermal sensors (PT100) for temperature monitoring.

How do AIC Tech's capacitors handle high ripple currents and what makes them suitable for such applications?

Our Power Film Capacitors, particularly the MLCA series, are designed for high ripple current applications. They utilize segmented metallized film technology, which enhances their ability to withstand high ripple currents without degradation. This design ensures stable performance and longevity even under fluctuating electrical loads.

How do AIC Tech's capacitors perform in harsh environmental conditions, such as high humidity or corrosive atmospheres?

Our capacitors are designed to operate within specified humidity ranges and should not be exposed to corrosive atmospheres. Models like the MKCP4T series are specifically designed for humidity resistance. Proper environmental controls and regular maintenance are essential to ensure reliable performance in harsh conditions.

Can these capacitors be used in applications involving high-frequency currents or harmonics?

Yes, AIC Tech's capacitors can be used in applications involving high-frequency currents or harmonics. However, it is essential to consider the impact of frequency on the capacitors' performance and ensure that the capacitors are selected based on their ability to handle the specific frequency and harmonic conditions of the application.

What is the typical lifespan of these capacitors, and how does operating temperature affect their longevity?

The typical lifespan of AIC Tech's capacitors ranges from 4,000 to 20,000 hours, depending on the series and operating conditions. Operating temperature significantly impacts longevity; capacitors should be used within specified temperature ranges to avoid thermal overload, which can reduce lifespan. Proper cooling and maintaining temperatures within the recommended limits are crucial for maximizing capacitor life.

Are these capacitors compliant with environmental and safety standards, such as the RoHS directive?

Yes, AIC Tech's capacitors comply with the RoHS directive, ensuring they do not contain hazardous substances like PCB or other toxic materials. This compliance guarantees that the capacitors meet environmental and safety standards, making them safe for use in various applications.

Power film capacitors are a special class of plastic film capacitors designed for high-power and high-voltage applications. Like all capacitors, they store and release electrical energy, but these devices are built to handle large reactive power levels (often 200 VA or more) in demanding power electronic circuits. Constructed with thin polymer film (usually polypropylene) as the dielectric and metallized electrodes, power film capacitors can be made in robust packages (e.g. rectangular box or cylindrical can) with secure terminals for heavy current connections. Their basic function in circuits ranges from smoothing out voltage fluctuations and filtering noise, to providing energy buffers in DC link and pulse discharge applications. In essence, a power film capacitor acts as a reliable energy reservoir that maintains stable voltage and reduces ripple in high-power systems.

Key Technical Advantages

Power film capacitors offer several technical advantages that make them well-suited for demanding environments:

High Voltage & AC Capability:

They are non-polarized and can withstand kilovolt-class voltages, allowing use in AC or DC circuits where electrolytic capacitors cannot operate. This high dielectric strength (polypropylene film can handle ~650 V/µm) enables capacitance solutions for multi-kilovolt applications.

Low Losses (High Efficiency):

These capacitors exhibit very low dissipation factors (tan δ) and minimal ESR (Equivalent Series Resistance), which means low self-heating even under large ripple currents. The low losses translate to high efficiency, crucial for modern power converters with fast switching (including SiC/GaN-based systems).

High Ripple Current & Fast Discharge:

With inherently low ESR and ESL (Equivalent Series Inductance), power film capacitors can supply high surge or pulse currents and handle rapid charge/discharge cycles without significant performance degradation. Their electrode structure yields a short current path, supporting use at higher frequencies (into the hundreds of kHz or even MHz range) for filtering applications.

Long Life & Reliability:

Built with self-healing metallized films, they can localize dielectric breakdowns – a tiny internal arc will vaporize the metallization around a fault, isolating it so the capacitor continues functioning with only a minor capacitance loss. This gives power film capacitors a very long service life and a soft end-of-life failure mode (gradual capacitance fade rather than sudden failure). They age slowly and offer higher reliability under stress compared to many other capacitor types.

Thermal Stability:

Quality film capacitors have stable capacitance over a wide temperature range and can operate in harsh conditions (often -40°C to +105°C, with some specialized types even higher). They resist thermal runaway and maintain performance under high ambient temperatures and high humidity (with certain series designed for added humidity resistance). This stability ensures consistent behavior in high-efficiency power systems that generate significant heat.

Major Application Areas

Power film capacitors are employed across a broad range of power electronics applications where their characteristics are indispensable:

Renewable Energy Systems:

In solar inverters and wind turbine converters, large film capacitors serve as DC link capacitors and filter banks to stabilize voltage and smooth out fluctuations from intermittent energy sources. Their high efficiency and long life make them ideal for these systems, which demand minimal losses and low maintenance over decades.

Motor Drives and Inverters:

Industrial motor drives, electric vehicle traction inverters, and high-power UPS systems rely on film capacitors for output filtering and DC bus support. Since the output of motor drive inverters is AC, non-polarized film capacitors must be used to absorb voltage spikes and filter EMI, a role electrolytics cannot fill. These capacitors handle high dV/dt and ripple currents, ensuring smooth torque and stable operation in motors.

Power Factor Correction & AC Filtering:

Power film capacitors are widely used in AC power conditioning – for example, in power factor correction (PFC) units, LC filters, and harmonic filters on industrial power lines. They can continuously withstand large reactive currents, helping improve power quality and reduce losses in factories and grid systems. Typical designs for such uses are heavy-duty metallized polypropylene can capacitors with screw terminals, built to endure high stress in traction systems, renewable energy farms, and grid applications.

Pulsed Power and Specialty Equipment:

Thanks to their ability to deliver high surge currents, power film capacitors find use in pulse-forming networks for lasers, radar, medical imaging (X-ray machines), and other specialty pulsed power applications. They charge to high voltages and discharge rapidly without damage. Additionally, smaller film capacitors serve in snubber circuits (protecting semiconductor switches from transients) and in EMI suppression, where reliability is paramount.

Reliable Solution for High-Efficiency Systems

In modern power systems that demand high efficiency and reliability, power film capacitors have established themselves as a core enabling component. Their combination of low electrical losses and robust self-healing construction means they contribute very little heat or failures even under heavy electrical stress. This translates to capacitors that run cooler and last longer, reducing downtime in critical equipment. Indeed, power film capacitors are often chosen for designs utilizing the latest high-speed, high-temperature semiconductors (e.g. in electric vehicle drives or aerospace power units) because they can meet the stricter requirements for stable, long-term performance where other capacitor technologies would struggle. By buffering energy and filtering out voltage ripple with exceptional consistency, these capacitors help maintain high conversion efficiency and protect sensitive components downstream.