What is an SMPS?

Switched-mode power supplies (SMPS), sometimes called switch mode power supplies, have become essential in efficient power conversion. They convert mains voltage AC input into a low-voltage DC output and are widely used in industrial applications like 3D printers, embroidery machines, irrigation systems, and more. Unlike older linear power supplies, SMPS are compact, efficient, and flexible, making them the preferred choice in modern designs.

How Does an SMPS Work?

Traditionally, linear power supplies performed the task of power conversion. These systems used heavy and bulky transformers with analog regulation circuitry and operated with conversion efficiencies below 65%. This low efficiency led to significant waste heat, requiring extensive cooling mechanisms.

In contrast, SMPS achieve efficiency levels typically above 85%, with some designs reaching 95%. Their lightweight, compact form factor and high efficiency make them ideal for modern industrial applications. Moreover, advances in semiconductor technologies, such as silicon carbide (SiC) and gallium nitride (GaN), have further enhanced SMPS efficiency and reduced their size.

Should You Build or Buy an SMPS?

During product development, engineering teams often face the decision to design or purchase a power supply. While designing an SMPS in-house can offer customization, it demands specialized expertise. Years of experience are required to create a reliable, efficient SMPS. Given the complexity of switched-mode designs, coupled with innovations in semiconductor technology, purchasing an off-the-shelf power supply is often the most practical and cost-effective solution for most industrial applications. For instance, DIN rail switching mode power supply options are readily available and offer reliable performance in industrial settings.

What Are the Principles Behind Switched-Mode Conversion?

Switched-mode principles apply to both AC-DC and DC-DC power supplies. For AC-DC supplies, the process involves rectifying the input AC voltage—whether single-phase 230V or three-phase 400V—before the DC-DC conversion stages.

In DC-DC conversion, power semiconductors generate high-frequency alternating voltage for a transformer. The transformer’s winding ratio determines whether the voltage is stepped up or down. The resulting high-frequency voltage is rectified and regulated to meet the output requirements.

Which Converter Topologies Are Most Common in SMPS?

Several topologies are used in SMPS, each suited for specific tasks:

Buck Converter: Steps down the input voltage. A combination of inductors and capacitors creates a smooth output, minimizing ripple.
Boost Converter: Steps up the input voltage to achieve a higher output.
Buck/Boost Converter: Capable of stepping up or down the input voltage.
Flyback and Quasi-Resonant Topologies: Common in isolated AC-DC applications, offering high efficiency and safety.

What Are the Functional Blocks of a switch-mode power supply?

Input Filter: Protects the system from voltage transients and surges while reducing electromagnetic interference (EMI).
Rectification: Converts AC input to pulsating DC and smooths it using bulk capacitors.
Power Factor Correction (PFC): Ensures compliance with regulations and improves efficiency by shaping the input current waveform.
Switching Function: Includes power semiconductors and transformers to convert and regulate the output voltage.
Output Regulation: Ensures a stable DC output through feedback loops and smoothing components.

How to Select a Suitable SMPS?

When choosing an SMPS for industrial applications, several factors must be evaluated:

Electrical Specifications: Input/output voltage, power handling, and efficiency.
Regulation: Ensure the output voltage remains within specified limits under varying load conditions.
Peak Output Capability: Some designs support short-duration peak loads, which can optimize cost and performance.
Compliance: Verify adherence to safety and energy efficiency standards like IEC 62368-1, DoE Level VI, and EcoDesign 2019/1782.

DIN rail SMPS options are particularly suited for industrial environments where space-saving and standardized mounting are important.

Conclusion

Switched-mode power supplies are a reliable, efficient solution for powering industrial equipment such as 3D printers, embroidery machines, and irrigation systems. With a wide range of input and output configurations, products from reputable suppliers like NVVV ensure compliance with safety and performance standards. For assistance in selecting the right SMPS, consult with power specialists to match your specific requirements.