#立创电赛# Forward CNC constant voltage and constant current adjustable power supply function machine with AC input

Note: * is a required field.
[Please fill in the form during the registration phase↓]
* 1. I am an electronics enthusiast. I was originally scheduled to study physical chemistry in Japan this spring, but was delayed due to the epidemic. I learned some electronics knowledge because of my hobbies before, and I am familiar with the magnetic devices and loop design theory of switching power supplies.
* 2. This project is going to design a single 220V input (195VAC~265VAC) forward digital control adjustable power supply. The design power should be 200W~300W. The output voltage is adjusted by the optocoupler feedback after PWM+ analog conditioning by the microcontroller. APFC chooses the common CCM mode boost, and the DCDC topology is ready to be selected from the dual-tube forward and single-tube forward, because compared with the bridge topology, there is no risk of direct pass, and the current mode is used to achieve better loop response and cycle-by-cycle current limiting. An adjustable power supply that can connect two channels in series and parallel is very practical, but it is still difficult to implement. Prepare to realize a single-channel output first, and add another channel if there is spare capacity.
【Please fill in during the competition stage↓】
* 1. Describe the project details.
A 40V5A CNC adjustable power supply was made, supporting an input voltage of 185VAC~265VAC, with a maximum efficiency of over 87%, a maximum power factor of over 98%, and a small size. The motherboard outside the display part is only 10cm*10cm*3cm (the size of the CNC board can be optimized, and even if a cooling fan is installed, the volume is still small), and the transient response is excellent. This project hopes to help the majority of power supply enthusiasts and engineers master and consolidate the classic power supply design and theory.
* 2. Describe the challenges faced by the project and the problems solved .
Most of the adjustable power supplies on the market use a flyback structure, which has a slow response speed, a large size, no PFC and a low power factor. Most importantly, it is difficult to find related open source products.
This power supply uses a commercial PFC+PWM chip CM6800, uses a continuous mode PFC+current mode single-tube forward topology, uses ferrite for magnetic components, and uses a newer process for the switch tube and rectifier diode. The switching frequency is set to 100kHz, which increases efficiency and reduces volume (half-load efficiency exceeds 87%).
* 3. Describe the key points involved in the hardware and software parts of the project.
Many friends' CNC parts use cool screens with various high-end functions, but I adopted a low-cost solution to control the total cost of the microcontroller and display part to less than 4 yuan. The microcontroller uses the domestic 51 microcontroller HC89S003, which costs only 80 cents. Although its routines are complete, the EC11 knob and state machine parts need to be written slowly by yourself, which is still quite cumbersome. The digital tube display driver is transplanted based on the open source project of micespring (from the STC microcontroller).
Of course, the core of this project is the analog part. The primary feedback loop also needs to be built by yourself. The loop stability and the design of magnetic components are quite challenging, which are also the two cores of power supply design.
* 4. The project material list is shown
in the project BOM. The transformer winding specifications are also included in the attachment.
* 5. Upload project pictures
          5.2. Other project pictures
Transformer field
calculation book (draft, I plan to organize and record the final draft and upload it to B station before October 10)
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* 6. Demonstrate your project and record it as a video and upload it
6.1. Upload the video to the official website of the competition
6.2. B station video title and link
https://www.bilibili.com/video/BV1Mt4y1q72o< br>
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Notes: ①: Video requirements: Please shoot in horizontal mode, with a resolution of no less than 1280×720, in Mp4/Mov format, and a single video size limited to 100M; ②: Video upload: Please upload to the official website of the competition and Bilibili (www.bilibili.com) simultaneously. The top 10 most popular projects on Bilibili will receive a cash reward of RMB 1,000-5,000, and other uploaded projects will receive a RMB 100 EasyChuang Mall no-threshold coupon; ③: Video title: The 5th EasyChuang Electronic Design Competition: {Project Name}-{Video Module Name}; such as the 5th EasyChuang Electronic Design Competition: "Autonomous Driving" project-Team Introduction.
* 7. Is this the first public release? 7.1
. First public release, the design was started after registration
* 8.
See the attachment for the open source document.
The open source project of the panel is here
https://oshwhub.com/eaea/shuo-kong-dian-yuan-mian-ban_copy_copy * 9. References 1. Liu Shengli, Li Longwen. Application of new technology of high-frequency switching power supply [M]. China Electric Power Press, 2008. 2. Sanjaya Maniktala. Mastering switching power supply design [M]. People's Posts and Telecommunications Press, 2008. 3. Zhang Weiping. Modeling and control of switching converters [M]. China Electric Power Press, 2006. 4. Ma Guosheng, Tian Ye. CM6800 power supply controller and its application in high-power switching power supply [J]. Electronic Design Engineering, 2004, 000(001):38-42. 5. Yang Cai. Research on topology and control algorithm of single-phase Boost power factor correction circuit [D]. Zhejiang University, 2012. Click the link for more details: https://www.szlcsc.com/go/dsxq