I. How to Choose a Suitable Power Module
How do we choose the right power module? Factors to consider when selecting a power module:
1. Rated power
It is generally recommended to use 30% to 80% of the rated power of the module power supply.
2. Operating frequency
Generally, the higher the operating frequency, the lower the output ripple noise, but the higher the requirements for component materials, so the higher the efficiency, the more expensive it is.
3. Power loss and efficiency
Under the condition of a certain output power, the lower the module loss, the higher the efficiency, the lower the temperature rise, and the longer the life.
4. Packaging Form
The system should be as small as possible under certain power conditions, ensuring system safety and reliability, and possessing scalability.
5. Temperature range
Generally, there are three grades to choose from: commercial grade, industrial grade, and military grade. The choice should be made based on the actual operating temperature range required. Different temperature grades use different materials and processes, and the prices of different grades vary considerably.
6. Isolation voltage
A high isolation voltage ensures lower leakage current, higher safety, reliability, and EMC characteristics for the power module.
7. Stability and reliability
When designing a product, it's important to consider how well it performs in harsh environments or extreme situations.
Factors to consider when choosing a power module manufacturer:
1. Consider your own requirements for the product.
Compared to domestic brands, foreign brands generally have higher product quality, but longer delivery times and higher prices, while domestic brands offer faster delivery and lower prices.
2. Examine the product design standards.
Modular power supply design is a very rigorous process, involving standards such as reliability design standards, derating standards, electrical safety standards, and EMC standards. It is advisable to communicate with the manufacturer's designers before purchasing.
3. Examine the materials used in the product.
The quality and positioning of a power module manufacturer can be seen from the materials used; good materials determine good quality.
4. Check the product certifications.
A good certification tests a manufacturer's technical standards. Product certification is expensive, and they will verify manufacturers from time to time, so it is trustworthy.
In terms of output and quality, large brands and manufacturers are definitely the first choice, whether in a single field or a general field, since the rule of "you get what you pay for" still applies in the market. However, this does not mean that products from small brands and manufacturers are not good products. Some small manufacturers use better materials than large manufacturers, and their technical specifications are above average.
However, large manufacturers have many advantages that smaller manufacturers cannot match. For example, in the procurement of key components, they can often purchase products from major brands at lower prices, while smaller manufacturers would have to pay higher prices to use these materials. Their production is also relatively professional, and they have more experience in quality control of large-volume products.
II. Power Module Reliability Testing
Reliability testing is a crucial component of power module testing, serving as an important method for assessing the stability and operational status of power modules. As testing requirements for power modules become increasingly stringent, utilizing a power module testing system can improve testing efficiency, ensure the reliability of test results, and meet testing requirements.
1. Short circuit test
Short-circuit testing is used to check whether the power module can protect or retract under short-circuit conditions. Short-circuit testing includes no-load to short-circuit test (short-circuit time 1s, release time 1s, duration 2 hours), full-load to short-circuit test (maintaining short-circuit state for 2 hours), and short-circuit to start-up test (repeated 10 times).
2. Repeated power-on/off test
Under maximum load, with input power of 220V, input overvoltage point -5V, and input undervoltage point +5V, the power supply is connected for 15 seconds and disconnected for 5 seconds, and then continuously run for 2 hours to test whether the power module can work properly.
3. Input transient high voltage test
Input the rated voltage, record the number of high-voltage cycles with an oscilloscope, run at full load, and continue running with voltage jumps.
4. Input power instability and output dynamic load test
The input voltage is adjusted to an unstable switching mode, and the output is adjusted to a maximum load and no-load switching mode for continuous operation.
5. Power waveform test
Simulate spikes, glitches, and harmonic voltage inputs to test power supply performance and parameters, check components, and resolve other issues.
6. Voltage test
Test multiple operational overvoltages to see their impact on the equipment.
7. High and low temperature tests
Due to abnormal performance parameters of components under high and low temperature conditions, long-term testing may expose potential problems with the product.
8. Insulation strength test
Based on the increase in the insulation strength of the product, continue testing to obtain the limit values and abnormal conditions.
9. Anti-interference test
The anti-interference voltage is set to different voltage levels using EFT, and continuous impulse resistance tests are conducted.
10. Input low-pressure test
Test whether the power supply module is continuously under-voltage input. If it is in an under-voltage state for a long time, will it affect the performance parameters of the power supply?
