منابع تغذیه بدون‌فن و مقایسه آن‌ها – The Solution of Fanless SPS and Application

modir 1403/03/30

By Dr. Leon Ku/Research and Development Dept.

Normally, SPS with fan built-in has a certain weakness such as unavoidable noise, vibration, additional power consumption, unexpected mechanical failure, short term reliability, dust debris, etc. On the contract, fanless SPS are smaller, more reliable and more flexible with lower noise. For the understanding of thermal characteristics of fanless SPS and SPS with fan built-in, different thermal dissipation methods of SPS will be introduced below.

به طور معمول، SPS (منبع تغذیه سوئیچینگ) مجهز به فن خنک کننده دارای نقاط ضعف خاصی مانند صدای غیرقابل اجتناب، لرزش، مصرف برق اضافی، خرابی مکانیکی غیرمنتظره، قابلیت اطمینان کوتاه تر، گرد و غبار و غیره میباشد. بطور متقابل، SPS های بدون فن دارای سایز کوچکتر، قابلیت اطمینان بالاتر و انعطاف بیشتر با نویز کمتر هستند. برای درک ویژگی های حرارتی SPS بدون فن و SPS با فن داخلی، روش های مختلف اتلاف حرارتی SPS در زیر معرفی می شوند.

SPS efficiency and power loss

Efficiency is the percentage ratio of total output power to input power. This is normally specified at full load under nominal input voltage. It is impossible to attain 100% efficiency due to energy dissipated in the form of heat in passive and active components, such as switching devices, junction-based devices, capacitors, inductors, and so on. However, it is still possible to achieve above 95% efficiency by suitable electrical design, thermal design and component chosen. Electric characteristic and dissipation could be affected due to low energy efficiency, and excessive power loss can even decrease the life time of power supply, as well as deviation of electric characteristic performance.

بازده، درصد نسبت کل توان خروجی به توان ورودی است و بطور معمول در بار کامل تحت ولتاژ ورودی اسمی اندازه گیری می شود. دستیابی به راندمان 100٪ به دلیل انرژی تلف شده به صورت گرما در اجزای غیرفعال و فعال مانند اجزاء سوئیچینگ، اتصالات، خازن ها، سلف ها و … غیرممکن است. با این حال، هنوز هم می توان با طراحی مدار مناسب، طراحی حرارتی و انتخاب اجزاء برتر و باکیفیت، به راندمان بالای 95% دست یافت. مشخصات الکتریکی و اتلاف می تواند به دلیل طراحی با راندمان انرژی کم تحت تأثیر قرار گیرد و اتلاف توان بالا حتی می تواند طول عمر منبع تغذیه را کاهش و همچنین انحراف عملکرد از کارایی الکتریکی مطلوب را سبب شود.

SPS power levels and thermal dissipation methods

Based on different application, thermal dissipation methods can be different. Generally, natural convection, forced convection, and water cooling are common thermal dissipation methods and possess different thermal dissipation capabilities. Please refer to the following description of comparison based on different thermal dissipation methods.

بر اساس کاربردهای مختلف، روش های انتقال حرارت می تواند متفاوت باشد. به طور کلی، جابجایی طبیعی، جابجایی اجباری و خنک‌سازی آب روش‌های متداول انتقال حرارت ایجاد شده هستند و قابلیت‌های انتقال حرارتی متفاوتی دارند. برای مقایسه روش های مختلف انتقال اتلاف حرارتی توجه شما را به موارد زیر جلب میکنیم.

(1) Comparison of heat transfer coefficient between different thermal dissipation methods:

Heat dissipation method	Heat transfer coefficient (W/m2K)
Natural convection	3-12
Forced air convection	10-100
Water cooling	3000-7000

(2) Comparison of heat dissipation capability between different thermal dissipation methods:

From the table and graph above mentioned, it is obvious that water cooling possesses higher thermal dissipation capabilities, but a higher cost on system mechanism design is expected. Comparison between three different thermal dissipation methods of SPS includes advantage, disadvantages, and applications as shown in the table below.

از جدول و نمودار ذکر شده در بالا، واضح است که خنک سازی با جریان آب دارای قابلیت انتقال اتلاف حرارتی بالاتری است، اما هزینه بالاتری در طراحی و اجرای آن انتظار می رود. سه روش مختلف انتقال اتلاف حرارتی SPS شامل مزایا، معایب و کاربردهایی هستند که در جدول زیر نشان داده شده اند.

Convection	Advantages	Disadvantages	Applications
Natural convection (Passive)	Widely available Low Cost No extra power consumption No acoustic noise and vibrations, silent operation Minimal maintenance Simple construction, easy installation	Low heat dissipation capability Large heat dissipation area requirement Strongly orientation dependence Hard to control the efficiency of heat dissipation under different environmental conditions Convection surfaces must be free from debris and corrosion	Low power density applications No noise, vibration requirements, such as low power medical equipment, indoor lighting, home electronics, security, precision, instruments, etc
Forced air convection (Active)	Lower thermal resistance for the same volume compared to passive thermal dissipation methods Greater thermal dissipation capability compared with passive thermal dissipation methods Customized cooling performance	Short term reliability Costly Require regularly maintenance and replacements Foreign object debris such as dust Acoustic noise and vibrations Require an additional energy source for operation	Medium to high power density applications Systems with existing air flow Normally used in Industrial equipment, information and communications, outdoor lighting, etc
Water Cooling (Active)	Much greater heat dissipation capability High thermal dissipation efficiency No noise and vibration, quiet operation Effective cooling with high ambient temperatures Increase of SPS lifetime Very wide operating temperature range	Complexity Costly Susceptibility to leaks Require an additional external liquid chiller	High to ultra power density applications Low profile applications Require constant heat cycling equipment Harsh Environments Mostly used in the high power industrial equipment such as industrial laser, charging station, etc

The brief introduction of MEAN WELL high power fanless SPS products

The features of UHP/PHP series SPS are shown below include smaller dimension (size reduction about 50%), high operating efficiency, wider temperature operating range, covering wide safety approvals and high value (performance/price) for all kinds of applications. The UHP/PHP series are the best choices for integrated into your end system.

• Compact design to provide the solution for modern miniaturized equipment

• Fanless design is suitable for equipment used in a silent environment and increased reliability in the system as an extra benefit

• High efficiency and low power consumption to allow better energy saving on the final system

• -30 ~ +70 ℃ wide operating temperature suitable for various environments or installations

• Certified by UL/TUV62368-1, IEC/EN60950-1 regulations

• Meet IEC/EN60335-1, EN61558 OVC III regulations

• Operational altitude up to 5000m

UHP/PHP series SPS have fanless and half encapsulated design, can provide the best solution for precision instruments, charging stations, distribution board/cabinet, robot applications for industrial4.0 and ITE equipment.

The brief comparison show in the table below gives the quick reference of UHP/PHP series SPS to identify the major difference:

	UHP-500	UHP-750	UHP-1000	UHP-1500	UHP-2500	PHP-3500
Cooling method	Passive cooling	Passive cooling	Passive cooling	Passive cooling	Passive cooling	Water cooling
AC Input voltage	90 ~ 264	90 ~ 264	90 ~ 264	90 ~ 264	90 ~ 264	90 ~ 264
Output voltage	4.2 / 5 / 12 / 15 / 24 / 36 / 48	12 / 24 / 36 / 48	24 / 48	24 / 48	24 / 48	24 / 48
Efficiency	95%	95%	96%	96%	96%	96%
Communication interface	─	─	─	CANBus PMBus	CANBus PMBus	CANBus PMBus
Dimension (L x W x H mm)	2328131	23710041	24011541	29014041	31014060	38014060