DC-DC module power supplies are increasingly being used in industries such as telecommunications, industrial automation, power control, rail transportation, mining, and defense. Their modular design effectively simplifies customers' circuit design while enhancing system reliability and maintenance efficiency. At the same time, due to the distinct characteristics of different sub-industries, their requirements naturally vary. This article primarily focuses on the selection of power modules for the power industry.
DC-DC module power supplies are increasingly being used in industries such as telecommunications, industrial automation, power control, rail transportation, mining, and defense. Their modular design effectively simplifies customers' circuit design while improving system reliability and maintenance efficiency. At the same time, due to the distinct characteristics of different sub-industries, their requirements naturally vary. This article primarily introduces the selection criteria for power modules in the power industry.
Due to the complexity of power grids, the power industry has diverse requirements for DC-DC power supplies. Below, the editorial team at Yulin Technology briefly outlines several key selection criteria:
1. Low No-Load Power Consumption
Certain monitoring devices in the power industry only activate during abnormal conditions and require significant power, but remain in standby mode for extended periods during normal operation, such as FTUs and anti-voltage-sag modules. Most such systems use batteries as backup power sources. If the no-load power consumption of the DC-DC module is too high, it can lead to issues such as short battery runtime and premature battery failure. For example, in a certain anti-flicker module project, when a power outage occurs, the power module must supply approximately 20W of power to the relay within 1.5 seconds; however, most of the time, the relay does not activate, and the system operates near no-load conditions. In this scenario, the battery's energy is consumed by the DC-DC module; the higher the no-load power consumption, the shorter the battery runtime. To extend battery life, the power supply's no-load power consumption must not exceed 0.3W, whereas commercially available 20W power supplies typically have no-load power consumption ranging from 0.5W to 1.5W.
2. High Efficiency Across the Entire Load Range
As mentioned above, many devices in the power industry operate under light load or even no-load conditions for extended periods. Therefore, achieving high efficiency across the entire load range is crucial for the reliability of the power supply system. However, this aspect is often overlooked by most power supply manufacturers. To make their technical specifications more appealing, many manufacturers focus on achieving very high efficiency at full load, but efficiency drops significantly under light loads (5%–50%). This results in higher actual operating temperature rises in the power supply module, leading to a series of thermal design issues. In fact, for power supply systems, high efficiency across the entire load range translates to lower power losses and temperature rise, effectively enhancing system reliability. Therefore, when selecting a power supply, special attention must be paid to its efficiency curves under no-load and light-load conditions.
3. High Isolation Voltage, Low Isolation Capacitance
In the industrial control sector, DC-DC power modules typically require an isolation voltage of only 1500 VDC. However, control systems in the power industry generally select power modules with a withstand voltage of 3000 VDC or higher to ensure the control system remains unaffected by external interference.
For power electronics products, it is also important to minimize parasitic capacitance between the primary and secondary sides. This requires selecting power modules with the lowest possible isolation capacitance to reduce the impact of common-mode interference on the system. Generally, for 1–2 W unregulated open-loop DC-DC converters used to power drivers, it is recommended to select modules with an isolation capacitance below 10 pF, while for closed-loop DC-DC converters, modules with an isolation capacitance below 150 pF should be selected whenever possible.
4. EMC Characteristics
EMC performance ensures the normal and safe operation of electronic systems. Currently, the electronics industry imposes stringent requirements on product EMC performance. Poor EMC handling can lead to system resets, reboots, or even premature failure; therefore, excellent EMC characteristics can enhance the competitiveness of power products.
5. Temperature Limit Characteristics
Power industry products are deployed across a wide range of geographical regions, from the scorching heat of tropical Hainan to the bitter cold of northeastern winters, and most products are installed in outdoor environments. Therefore, DC-DC module power supplies must have an operating temperature range of at least -40°C to +85°C.
Extreme temperature testing is a method to verify the reliability of power modules, including high-temperature aging, high- and low-temperature live-load performance testing, high-low temperature cycling shock tests, and long-term high-temperature and high-humidity testing. Proper power supply development undergoes all of these tests. Conducting these reliability tests provides important reference for product selection.
The selection of DC-DC power modules must account for the specific characteristics of the power industry. For instance, if the overall power system requires greater energy efficiency, power modules with high efficiency and low no-load power consumption are necessary. Additionally, the stability of the system under various EMC interference conditions must be considered, necessitating power modules with excellent EMC performance. Similarly, while a power module is merely a functional component, enhancing the reliability of the power system requires a more comprehensive approach that considers system-level application design.