Hydrogen Energy and Power Supplies System
Global warming and extreme climate phenomena, net-zero carbon emissions have been the goal of countries in the world. Among alternative solutions for fossil fuels, Hydrogen Energy has attracted widespread attention.
The main reason is Green Hydrogen Energy with zero carbon emissions which has significant application opportunities in the fields of renewable energy, industry and transportation. Therefore, hydrogen energy is considered one of the key solutions to address energy issues.
Hydrogen Types
Hydrogen atoms are present in common compounds such as water, methane and ethanol. Currently, there are two hydrogen production technologies: Electrolysis and Steam Reforming. According to hydrogen production methods and carbon emissions, hydrogen can be categorized into Grey Hydrogen, Blue Hydrogen and Green Hydrogen, as shown in Figure 1.
Grey Hydrogen is the most common way of producing hydrogen. The raw materials for hydrogen production are fossil fuels such as coal, oil and natural gas. The cost of converting hydrogen through chemical reactions is relatively low. However, this method generates a significant amount of carbon dioxide emissions. Similar to grey hydrogen, Blue Hydrogen also uses fossil fuels to produce hydrogen. However, it incorporates carbon capture processes to capture and store the produced carbon dioxide, which can reduce carbon dioxide emissions. Green Hydrogen utilizes renewable energy to electrolyze water, producing hydrogen with almost no carbon emissions in the process. Therefore, it is the most environmentally friendly way to produce hydrogen.
Figure1. Hydrogen Types
Introduction of Electrolysis Hydrogen and Fuel Cell
The field of hydrogen energy can be divided into electrolysis hydrogen production and fuel cell applications. Commonly used electrolysis hydrogen production technologies include [1-2]:
1) Polymer electrolyte membrane electrolysis, PEM-EL: It uses a solid acid polymer membrane as the electrolyte. Water is electrolyzed at the anode into hydrogen ions and oxygen and releases electrons. Hydrogen ions migrate to the cathode through the proton exchange membrane and combine with electrons conducted by the external circuit to generate hydrogen gas. This technology has the advantage of high electrolysis efficiency due to its high current density characteristics. The cell voltage range of PEM electrolyze is between 1.8 V and 2.5 V.
2) Alkaline electrolysis, A-EL: It uses potassium hydroxide as the electrolyte. Hydroxide ions migrate to the anode through the porous conductive membrane, where they undergo an oxidation reaction to release electrons to generate oxygen. Water is electrolyzed into hydrogen ions and hydroxide ions at the cathode and accepts electrons to release hydrogen. Currently, it is mainly used in large-scale electrolytic hydrogen production systems. The cell voltage range of AEL electrolyze is between 1.4 V and 3.0 V.
3) Anion exchange membrane, AEM-EL: It combines the low cost of an AEL with the simplicity and efficiency of PEM. Using non-noble metal catalysts and titanium-free components, it can operate under pressure differences like PEM. AEM has low conductivity, slow catalytic kinetics and poor electrode structure which affects the performance of AEM. The cell voltage range of AEM electrolyze is between 1.4 V and 2.0 V.
4) Solid oxide electrolysis, HT-EL: It uses ceramic materials that conduct oxygen ions as electrolytes. Water enters the electrolyze in the form of steam and it is electrolyzed into hydrogen ions and oxygen ions at the cathode. The hydrogen ions accept electrons conducted by the external circuit to generate hydrogen. This electrolysis method operates in a high temperature environment (700~1000℃). The cell voltage range of SOE electrolyze is between 1.0 V and 1.5 V.
Currently, electrolytic stack modules are mostly customized and towards high power development. Figure 2 is a structural diagram of an electrolytic stack. For example, a cell voltage is 2V and 48 cells are connected in series to form a 96V stack, which means a DC 96V power supply is required for electrolysis. Therefore, a longer stack length with a higher voltage is required. A larger number of stacks in parallel and a larger surface area imply that hydrogen electrolysis requires a higher electric current.
Figure 2. Structural diagram of an electrolytic stack
The hydrogen produced through electrolysis is transported either via hydrogen storage tanks or pipelines to various application sites. Currently, the most widely used application is in fuel cells. The fuel cell stack is composed of multiple plates and membranes. After adding hydrogen and oxygen into fuel cell, the chemical energy is converted into electrical energy for use. Fuel cells produce a typical voltage of around 1V. Stacking these cells creates a higher usable voltage. Currently, fuel cell stacks are mostly customized to fit various applications. Fuel cell types include phosphoric acid fuel cells (PAFC), molten carbonate fuel cell (MCFC), alkaline fuel cell (AFC) and proton exchange membrane (PEM) cell.
Figure 2. shows the fuel cell polarization curve [3]. As the current increases, the first voltage drop represents a loss of cell activation. The second part represents the voltage loss caused by internal resistance. The third part represents the voltage drop due to gas delivery or concentration loss. Table 1 shows a comparison of fuel cell stacks specifications from various manufacturers. The characteristic of a fuel cell stack is that the voltage decreases as the operating current increases. More stacks in a fuel cell stack means a higher power output of the fuel cell.
Figure 3. The fuel cell polarization curve [3]
Table 1. Comparison of fuel cell stacks specifications from various manufacturers
Hydrogen Energy Systems and Power Supplies Requirements
Figure 4. shows the hydrogen energy system and power supplies requirements [4], which can be divided into two applications: electrolysis power supplies and fuel cell power supplies. Electrolysis power supplies can be converted into electrical energy by grid-connected AC/DC converters, wind turbine AC/DC converters, solar DC/DC converters and battery DC/DC converters for electrolysis hydrogen. After a fuel cell generates electricity, it can be converted to the load through a DC/DC converter or a DC/AC inverter. In the selection of the electrolysis power supplies, constant current and programmable current control functions of power supplies are needed. In the selection of fuel cell power supplies, wide input voltage range and high-power rating of power supplies are requested, and the user should note that fuel cell stack voltage decreases with using life and ageing.
Figure 4. Hydrogen energy system and power supplies requirements
The feature of MEAN WELL power supplies is that a single model has multiple voltage models with a wide voltage range design to fit market applications. Users can achieve programmable output voltage (PV) and programmable output current (PC) functions for power supplies, which can be implemented through the communication interface and external voltage. The selection of power supplies for electrolytic hydrogen production can be divided into modular power supplies and centralized system power supplies. Figure 5. shows the modular power supplies used in electrolysis hydrogen. Taking MEAN WELL AC/DC power supply products DPU-3200 series and PHP-3500 series as an example, a single power supply can be used to correspond to one electrolytic tank to form a module. Modular power supplies provide more flexibility, allowing users to choose multiple independent modules or multiple parallel modules for high-power electrolysis hydrogen based on system power or configuration requirements.
Figure 5. The modular power supplies used in electrolysis hydrogen
Figure 6. shows applications of centralized system power supplies for electrolysis hydrogen. Taking the NCP-3200 series and SHP-30K series AC/DC power supplies as examples, they can be divided into two solutions: Single-phase AC and 3-phase AC input:
- Single-phase AC input : NCP-3200 series + DHP-1UT-B(HV)shelf + Controller_CMU2 + Rack Cabinet.
- 3-phase AC input : SHP-30K series + Controller_CMU2 + Rack Cabinet.
Above MEAN WELL (3+N) centralized system power configurations can provide up to 360KW. Multiple centralized system power supplies can also be configured according to factory requirements to achieve multiple high-power electrolysis hydrogen. Following with MEAN WELL AC-DC power supplies solutions for electrolysis hydrogen.
Figure 6. Applications of centralized system power supplies for electrolysis hydrogen
| Modular Power Supplies | |||
|---|---|---|---|
| 1): 3200W; Single phase AC input | 2): 3500W; Single phase AC input | ||
| DPU-3200 series | PHP-3500 series | ||
 |
DC output: 24V, 48V |
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DC output: 24V, 48V, 115V, 230V, 380V |
| (3+N) Centralized system power supplies | |||
| 1): Max. 320KW system power; DC output: 24, 48, 380VDC; Single phase AC input | |||
| NCP-3200 series | DHP-1UT-B (HV) | CMU2 | 19” Rack Cabinet |
 |
 |
 |
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| 2): Max. 360KW system power; DC output: 55, 115, 230, 380VDC; 3 phase AC input | |||
| SHP-30K series | CMU2 | 19” Rack Cabinet | |
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| 3): Others PSU; DC output: 55, 115, 230, 380VDC; 3 phase AC input | |||
| RST-15K series, SHP-10K series | CMU2 | 19” Rack Cabinet | |
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Table 2. MEAN WELL AC-DC power supplies solutions for electrolysis hydrogen
Figure 7. is an example of hydrogen electrolysis power supplies control. MEAN WELL (3+N) centralized system power supplies are used to perform hydrogen electrolysis with stacks. During the initial electrolysis process, the system power supplies current is adjusted according to the internal impedance and gas reaction of the electrolytic tank. Power supplies current changes from low current to high current over time to perform electrolysis. The advantage of MEAN WELL system power supplies is that the programmable output current (PC), which has an adjustable wide range, is 20%-100% of the load. Therefore, the system controller can control MEAN WELL system power supplies to perform electrolysis at a lower current level through communication. During the electrolysis process, the system controller will detect the parameters of gas and output current and output voltage of power supplies at any time into the system control loop, and then the system controller can control MEAN WELL system power supplies through communication to adjust the output current and voltage to achieve the optimal electrolysis efficiency.
Figure 7. Example of hydrogen electrolysis power supplies control
An example of fuel cell power supplies is shown in Figure 8. The characteristics of the fuel cell stack are a wide voltage range, and the voltage range of fuel cell stacks varies among different manufacturers’ designs. Therefore, taking MEAN WELL wide voltage range DC/DC power supplies DDRH series as an example, power energy generated by fuel cell will be converted into low voltage through the DDRH series high-voltage DC/DC converter and supply to various loads such as fans, DC motors, controllers and LCD monitor applications.
Generally, fuel cell systems will also be equipped with another high-power DC/DC converter to store the fuel cell energy into backup battery storage system for other DC loads. The new product of MEAN WELL is preparing to launch, the 2 in 1 design of high-power charger/Inverter with UPS, NTN-5K series, highlights its advantages. The wide DC input voltage range of DC/AC inverters can fit fuel cells applications. Inverter converts DC power into AC power, it can also support single-phase AC or 3-phase AC 90KW system applications through parallel connection. Table 3. shows MEAN WELL DC/DC and DC/AC power supplies for fuel cell solutions.
Figure 8. Example of fuel cell power supplies
|
DDR series |
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DC input: 16.8-33.6V; 33.6-67.2V; 67.2-154V DC output: 12V, 24V, 48V 4 units parallel application |
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DDRH series |
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DC input: 250-1500V DC output: 12V, 24V, 32V, 48V 4 units parallel application |
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RSDH series |
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DC input: 250-1500V DC output: 12V, 24V, 32V, 48V |
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SD series |
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DC input: 19-72V or 72-144V DC output: 12V, 24V, 48V |
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NTS series |
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DC input: 10-16V, 20-33V, 40-66V AC output: 100-120Vac; 200-240VAC Inverter function |
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NTN series |
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DC input: 20-33V, 40-66V, 280-430V AC output: 100-120Vac; 200-240VAC Build in inverter/charger with UPS |
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*For more details, please refer to MEAN WELL Virtual Expo |
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Table 3. MEAN WELL DC-DC and bidirectional DC-AC power supplies for fuel cell solutions
Conclusions
The feature of MEAN WELL power supplies is that single model has multiple voltage models with a wide voltage range design to fit market applications. Users can achieve programmable output voltage (PV) and programmable output current (PC) functions for power supplies which can be implemented through the communication interface and external voltage. Figure 8 shows the application combination of the hydrogen energy system and MEAN WELL power supplies. MEAN WELL power supplies have deployed AC/DC modular and 3+N system power products in the field of electrolytic hydrogen with a maximum capacity of up to 510 kW. DC/DC power supplies can provide up to 2KW and DC/AC inverter power supplies can provide up to 90KW for fuel cell applications.
Currently, MEAN WELL can provide more power supplies solutions based on customer application needs in the field of hydrogen electrolysis, fuel cells and renewable energy. For inquiries about related products and application requirements, you can directly contact MEAN WELL sales or technical staff. In addition, please stay tuned for MEAN WELL online exhibition hall relevant products and online courses for solutions.”
Figure 9. Application combination of the hydrogen energy system and MEAN WELL power supplies
References:
[1]. Energy Administration, Ministry of Economic Affairs, R.O.C，再生能源電解產氫之技術發展狀況。
[2]. 太原麗子，電解產氫技術簡介及日本發展現況研析。
[3]. H. E. A, A. C, C. S, A. P. N and E. G. “Thermal and Electrical Parameter Identification of a Proton Exchange Membrane Fuel Cell Using Genetic Algorithm”, 2018.
[4]. Hydrogen Technology Expo Europe 2023.
Learn more about Power Supplies used in Hydrogen
Explore our blog for insightful technical notes about Hydrogen Energy and Power Supplies.
Got questions?
Look at the section below to find the most frequently asked questions (with answers)
we received in Hydrogen Applications.
The GTIN number can be found directly on the www.meanwell.com:
Internally, IRM series has the following AC fuses, which are implemented on AC/L input:
| IRM-01/02/03 | T1A/L300V |
| IRM-05/10/15/20/30 | T2A/L300V |
| IRM-45/60 | T2.5A/L300V |
| IRM-90 | T3.15A/L300V |
Yes, MEAN WELL products are registered in SCIP. To get such information for specific power supply, please follow the steps below:
- Go to https://echa.europa.eu/en/scip-database
- Under SEARCH option, choose „Article Identity” and write down model name e.g. RSP-1600.
- As “Identifier type (optional)”, please chose “Other”
- Click “Search” button
The declaration of Five PBT TSCA Conformity can be found on the last page of Installation Manual e.g. below:
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MEAN WELL’s distributor information can be found on Distributor Network-MEAN WELL Switching Power Supply Manufacturer
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MEAN WELL has the largest distribution network for serving your small and medium demand Power Supplies. You can find all MEAN WELL’s distribution channels on Distributor Network-MEAN WELL Switching Power Supply Manufacturer.
OEM’s which have no sales channel for MEAN WELL products yet can contact us via the “Contact Us” form on this website.
MEAN WELL’s discontinued product schedule and End of Life products are normally updated 2 times per year, in January and in July and are published on www.meanwell.com. See FAQ “Where can I find MEAN WELL’s discontinued product schedule and End of Life information? “
The normal procedure for E.O.L. is:
- The product or series is announced in the Discontinued product list in January or July and announced as NRND (Not Recommend for New Design)
- 6 months later the lead time of the product or series will increase +30 days, the price will increase as well.
- Another 6 months later, the lead time will increase another +30 days (so + 60day compared to the original lead time), the price will increase again.
- Another 6 months later, the lead time will increase another +30day (so +90 days compared to the original lead time) and the price will increase again and additionally there will be a MOQ of 200pcs (and steps of 100 for higher quantities)
- After another 6 months the last buy is announced on the website. This will be the last opportunity to place an order for this product or series.
In total MEAN WELL’s End of Life, procedure will take 2 years. However, there are situations for instance that certification is expired, or some components can no longer be obtained by the market which will force to accelerate the EOL schedule. Therefore, it is always highly recommended from the moment that a product is on the discontinued list to design in one of our new generation products. If need any advice to this, please use the “Contact Us” function on this website.
MEAN WELL’s discontinued product schedule and End of Life products are normally updated 2 times per year, in January and in July. To see the full list, go to www.meanwell.com
1. Click on products
2. Click on Discontinued products for the schedule for the EOL schedule
Click on EOL for the MEAN WELL products which are End Of Life
You can use the “Contact Us” function on this website
MEAN WELL’s website provides you all the basic information about our Power Supplies. This includes company news, product announcements, ISO certificates, Specifications, test report, Certificates, ROHS declarations, Reach declarations and many more.
MEAN WELL’s products can be found on www.meanwell.com
1. Click on products and select the product category
Or in case you already have a part number, you can use the search function on the website:
2. Use the search function on the website to find the right product
3. Fill in the series number in the search field (do not include the last extensions such as -12 in XLG-150-12)
4. Click the search button
5. Click on the PDF icon to open the specification
MEAN WELL has several charger products, and we suggest choosing them first. Chargers would be more suitable since they are designed for charging applications. Safety and approvals should be taken into account based on the final application. If you are unable to find a proper model in our charger series, our LED CC models can be used as charger. Please choose suitable products after confirming the current and voltage specification on the datasheet of the battery.
All MEAN WELL chargers are preset for lead-acid batteries. For other products that can customize the charging curve (such as ENC / NPB series), customers can customize their charging curve depending on the charging and discharging characteristics of batteries. If you have other requirements, please use the contact us function on this website.
MEAN WELL has launched ENC, HEP-600C, GC, PA, PB, RPB and RCB series for battery charge applications (30~1000W). However, if these models cannot fulfill your requirements, there is an alternative solution. Power supplies with constant current limiting as overload protection are suggested. Charge current varies in battery percentage (full or flat), there is high possibility to trigger overload protection when battery is low, those with overload protection as hiccup or shutdown will stop charging the battery in low battery condition. Yet, using a power supply as charging purpose is considered as overload usage, modification is required. Please Contact Us for the request.
MEAN WELL’s Step files/ 3D files can be found on www.meanwell.com
- Use the search function on the website to find the right product
- Fill in the series number in the search field (do not include the last extensions such as -12 in XLG-150-12)
- Click the search button
- Click on the PDF icon to open the specification
- Click on 3D OUTLINE
- Click on the model XLG-150-3D to download the step file.
PMBus full name is Power Management Bus is an open standard for digital power management. The physical layer is based on I2C, and PM Bus had a set of commands that specifically design for power supply industry. More information can be found in https://pmbus.org/
MEAN WELL Rack Power and intelligent power supply and chargers have optional PMBus solution for example: PHP-3500 and HEP-1000 further the RCP/RSP-1600, UHP-2500 and DPU-3200 have this optional available.
A Controller Area Network (CAN Bus) is a bus standard initially developed for vehicle designed to allow multi-master with priority control without a host computer. The latest version is CAN 2.0 which consists of part A and part B. CAN 2.0A is for standard format with 11-bit identifier, and CAN 2.0B is for extended format with 20-bit identifier. CAN Bus is widely used in Automotive and industrial automation. There are not only 1 but many higher layer protocol such as CANopen, DeviceNet and more.
MEAN WELL CAN Bus product support CAN 2.0B (ISO-11898) with baud rate 250Kbps
MEAN WELL offers optionally CAN bus for PHP-3500, HEP-1000, RCP/RSP-1600, UHP-2500 and DRP/DPU-3200 and DBR/DBU-3200.
During safety verification process, the agency will use a stricter standard ±10% (IEC 62368 uses +10%, -10% for the product with AC input rated) of the input voltage range labeled on the power supply to conduct the test. So, operating at the wider input voltage range as specified on the spec. sheet should be fine. The narrower range of input voltage labeled on the power supply is to fulfill the test standard of safety regulation and make sure that users insert input voltage correctly.
Cooling fans have a relatively shorter lifetime (typical MTTF, Mean Time To Failure, of around 5,000-100,000 hours) compared with other components of power supply. As a result, changing operating method of the fans can extend the operation hours. The most common control schemes are shown as below:nnTemperature control: if the internal temperature of a power supply, detected by a temperature sensor, is over the threshold, the fan will start working at full speed, whereas, if the internal temperature is less than the set threshold, the fan will stop working or run at half speed. In addition, cooling fans in some power supplies are controlled by a non-linear control method whereby fan speed can be changed with different internal temperatures synchronously.nLoad control: if the loading of a power supply is over the threshold, the fan will start working at full speed, whereas, if the loading is less than the set threshold, the fan will stop working or run at half speed.
Yes, for power supplies certified >2000m please read the “note” in the spec.
In general, for unpotted models, a derating of 5°C/1000m has to be applied and for potted models, a derating of 3.5°C/1000m has to be applied.
For example LRS-75-24:
The datasheet shows:
The Note. 7 shows:
At 5000m the derating curve will need to move 15°C following the arrow (1)
At full load the maximum operating temperature at 5000m will be 35°C shown at (2)
Most MEAN WELL power supplies are certified to be operated till 2000m. For some models the certification is valid for a higher altitude, this will be shown on the first page of the power supply under features (1)(2).
Please note that derating is needed at an altitude above 2000m. See FAQ “Do I need to derate my power supply when I used it over 2000m?”
MEAN WELL’s specification shows the absolute values which were verified during design quality verification tests. Those condition are guaranteed by manufacture from quality and warranty perspectives.
When certifying a power supply according to a certain norm, there is normally a requirement described in this standard a certain tolerance which must be considered. (See also FAQ: Why Is The Input Voltage On The Label Different From The Input Voltage In The Spec? For Example, The Specification Shows Is 88~264 VAC While The Label On The Power Supply Says That It Is 100~240VAC?)
The specification shows what is possible, the report and label of the power supply shows what is approved by the certifying body according to the standards.
Besides the difference due to tolerance there might also be another reason why the specification and label/test report show a different temperature. For example, if the power supply needs to be derated at a low voltage input such as 100VAC, the label and test report might show the max temperature at full load based on this low input.
Different standards might have different tolerance requirements and different ranges this could mean that the most conservative value, or multiple values will show up on the label of the power supply.
MEAN WELL’s component self-heating can be found on www.meanwell.com
1. Use the search function on the website to find the right product
2. Fill in the series number in the search field (do not include the last extensions such as -12 in XLG-150-12)
3. Click the search button
4. Click on the PDF icon to open the specification
5. Click on report
6. Click on the model and scroll down:
7. The temperature of the critical component can be found in the chapter Reliability Test under item 1 Temperature Rise Test
For more details about the component type for each position, please use the Contact Us function on this website.
MEAN WELL’s MTBF can be found on www.meanwell.com
1. Use the search function on the website to find the right product
2. Fill in the series number in the search field (do not include the last 3. extensions such as -12 in XLG-150-12)
3. Click the search button
4. Click on the PDF icon to open the specification
Scroll down in the specification to the bottom of the second page
5. Find the MTBF value in under others:
MEAN WELL’s capacitor lifecycle calculation can be found on www.meanwell.com
1. Use the search function on the website to find the right product
2. Fill in the series number in the search field (do not include the last extensions such as -12 in XLG-150-12)
3. Click the search button
4. Click on the PDF icon to open the specification
5. Click on report
6. Click on the model and scroll down:
7. The Capacitor life cycle calculation is shown on the last page of the report in the chapter Reliability test
The Capacitor life cycle calculation is considered as the key indicator for the lifetime of the power supply. Please refer to the test report of the power supply on www.meanwell.com for the capacitor life cycle calculation.
As a rule of thumb, every 10dC increase the lifetime will be cut in half and vice versa for every 10dC decrease in temperature.
In the above example, if the power supply is used at 75dC at Ta 40dC, the estimated lifetime would be 2*104095 Hrs ~200K hrs.
In MEAN WELL’s specification you can find 2 derating curves, in below example the 300W open frame power supply: EPP-300
- The Derating Curve with the Ambient Temperature vs. Load
- The Derating Curve with the Input Voltage vs. Load
- In this Curve one can find that the maximum load of this power supply is 300W at 50dC when an external air flow of 20.5CFM is applied. For temperatures exceeding 50dC, 60dC for example additional derating need to be applied, in above case at 60dC the maximum load would be 225W. (50dC 300W, 70dC 150W => from 50dC to 60dC: 75W derating)
- In case this power supply would be used at 90VAC input, a derating of 80% must be applied. So, in previous example with the 20.5CFM forced air the max load would be 240W. In case of an ambient temperature of 60dC and a 90VAC input the maximum rated power would be 225W * 0.8 = 180W with 20.5CFM forced air.
- If the power supply is used in an application without additional forced Air, the power supply will be derated to 200W till a maximum temperature of 50dC
- In case it will be powered by a 90VAC input the power supply has to be additionally derated to 80% of the 200W = 160W max
MTBF (Mean Time Between Failure) and Life Cycle are both indicators of reliability. MTBF can be calculated by two different methodologies, which are “part count” and “stress analysis”. The regulations, MIL-HDBK-217F Notice 2 and TELCORDIA SR/TR-332(Bellcore) are commonly used to calculate MTBF. MIL-HDBK-217F is a United States military standard, and TELCORDIA SR/TR-332(Bellcore) is a commercial regulation. MEAN WELL utilize MIL-HDBK-217F(Stress Analysis) as the core of MTBF. The exact meaning of MTBF is, after continuously using the power supply for a certain amount of time, the average time that the probability of proper operation is down to 36.8%（e-1=0.368）. Currently MEAN WELL is adopting MIL-HDBK-217F, to predict the expected reliability through Stress Analysis (excluding fans); this MTBF means the probability of the product can continue the normal work after working continuously up to the calculated MTBF time is 36.8% (e-1=0.368). If the power supply is continuously used at double the MTBF time, the probability of proper operation becomes 13.5%（e-2=0.135.
DMTBF (Demonstrated Mean Time Between Failures) is a way of evaluating MTBF in a relatively short period of time based on accelerated deterioration (high stress, high temperature) tests under specific parameters and conditions. Please refer to the following equation for MTBF calculation.
This method compares to the previous methods, this calculation uses real test data to demonstrate the reliability of the power supply.
Where
MTBF： Mean Time Between Failure
- X2：Can be found in chi-square distribution
- N：Number of sampling
- AF：Acceleration factor, which can be derived from acceleration factor equation.
- Ae=0.6
- K(Boltzmann Constant)=(eV/k)
- T1：Rated temperature of specification. Note: Kelvin will be the unit use for calculation
- T2：The temperature that is used in the meaning of acceleration, and the chosen temperature could not result in physical change in materials.
Note: Kelvin will be the unit use for calculation.
Life Cycle (Capacitor Life Cycle) is found by using the temperature rise of electrolytic capacitors under maximum operating temperature to estimate the approximate life of the power supply. For example, RSP-750-12 MTBF=109.1K hours(25°C); electrolytic capacitor C110 Life Cycle=213K hours (Ta=50℃).
MEAN WELL considers the capacitor lifecycle calculation as the most important indicator for the estimated lifetime. The (D)MTBF is the main indicator for the reliability of the power supply. For more information please see: Investigation of The Lifetime & Reliability of Power Supply -MEAN WELL EUROPE Switching Power Supply
MEAN WELL’s safety reports, IEC reports and CB reports are not available online. In case you need these reports to validate your design with your certifying body, please contact your local MEAN WELL sales channel for support. If you are unable to get the support, please contact us via this website.
MEAN WELL’s User Manual can be found on www.meanwell.com
1. Go to products
2. Click on Installation Manual
3. Scroll down to find the user manuals for the different product families.
MEAN WELL’s Safety certifications can be found on www.meanwell.com
- Use the search function on the website
- Fill in the series number in the search field (do not include the last extentions suchs as -12 in XLG-150-12
- Click the search button
4. Click on the PDF Link
5. Click on the top on the certificate
6. All available certificates are shown and will show up once clicked upon
MEAN WELL’s CE declarations can be found on www.meanwell.com
- Use the search function on the website
- Fill in the series number in the search field ( do not include the last extentions suchs as -12
- Click the search button
4. Click on the PDF Link
5. Click on the top on certificate
6. Click on CE declaration
Select (1) Products followed by (2) downloads
MEAN WELL’s EMI test guide can be found on www.meanwell.com
Select (1) Products followed by (2) Downloads
After this scroll down to find the EMI testing of Power guide
Or you can use this link to directly download the EMI testing guide:
EMI_statement_en.pdf
MEAN WELL’s RoHS and Reach statements can be found on www.meanwell.com
Select (1) Products followed by (2) Downloads:
After this scroll down to find the RoHS declaration and Declaration of SVHC/ REACH conformity:
Or you can use the below links to download the declarations:
MEAN WELL’s Declaration of Conflict Free Minerals can be found on www.meanwell.com
Select (1) Products followed by (2) Downloads
After this scroll down to find the Declaration of Minerals Conflict Free
Or you can use this Link to directly download the EMI testing guide: