#SecondLichuangcompetition#AC/DC electronic load & power simulator

Design a device that can be used as both a CNC power supply and an electronic load to achieve two-way flow of power from the load to the grid; it can be used for battery charge and discharge cycle testing or the aging of the power supply; it enables the power supply to have a load function to reduce user duplication invest. Energy feedback reduces the size and weight of the equipment;   conceptual diagram of the work: Materials     currently on sale at Lichuang Mall to be used: STM32F051C8T6 MP2451DT-LF-Z ICL7660AIBAZA-T74HC164D TL084N... Non-Lichuang Mall materials or other supplements to be used: LM5101  

1. Introduction to the work . For example, it can include but is not limited to the following: 1. Pictures of the appearance of the complete machine or pictures of the welded and assembled PCBA;    next time                                                    the bare board                                                               is installed, be sure to use a laser to engrave a few samples of the casing and dig out a few samples. I've been working on this hole all afternoon, and NND's typing hands are shaking now. It’s really thankless, and several holes are crooked (┬＿┬) 2. Research background, purpose and function of the work, and market application prospects; Background: In the field of power supply testing, there is a large amount of aging needs. The traditional method is to use cement resistors or energy-consuming electronic loads for discharge testing, which not only consumes a large amount of electricity, but also causes environmental heating that greatly affects the comfort of people's workplaces. The existing energy regenerative loads on the market are limited to high-power applications, either with very high voltage or very large current. This kind of test requirements within tens of watts cannot be covered. This low-power scenario is the most common. It is therefore necessary to develop such a device. Achieve energy-saving, environmentally friendly and environmentally friendly power supply testing. Considering the needs of battery testing, the test equipment is required to be able to both output and input power. This is the original intention of this case design. Research purpose: Design and implement a four-quadrant bidirectional converter to simulate power supply and load functions. Forward energy transfer simulates a power supply, and reverse energy transfer simulates a load. That is to say, the device can work in power mode to supply power to the device, or it can work in electronic load mode to discharge the power supply. The source and load functions can be switched through panel button settings or communication commands to achieve dual uses in one machine and reduce repeated investment in equipment. At the same time, the electronic load discharge process is an energy-saving feedback type, which can reduce heat generation, achieve miniaturization of equipment, and greatly save users' electricity bills. Function: constant voltage and constant current power supply + constant voltage and constant current discharge energy-fed electronic load all-in-one machine Abbreviation: electronic load/power simulator Market application prospects: Taking a mobile power supply manufacturer as an example, it has a total of 10K point charge and discharge test ports . The power of each port is 10~20W, and the average value is 15W. The total discharge power is 150KW. The average electricity bill is calculated as 0.85 yuan, the working time of each port is 16 hours/day, and the calculation is based on 300 days a year. The total electricity bill is 150*16*300*0.85=612,000 yuan. Calculated based on an energy-saving feedback rate of 85%, the direct economic benefit is about 520,000 yuan. Reducing air conditioning and cooling costs is not included. The same case can also be applied to power adapter manufacturers, etc. ~ 3. What are the highlights of the work in terms of innovation, interest, practicality and even public welfare? Innovation: Integrated design of power supply and load. Interesting: Test tool, which doesn’t seem to be fun. Tool control exception. Public welfare: energy saving and emission reduction, reducing carbon dioxide emissions   2. System architecture diagram Use a flow chart or mind map to describe the structure of your work, that is, a plan diagram. System composition:   System detailed block diagram    Working principle The entire system consists of three major units: PWM rectifier + bidirectional DC/DC converter + active differential mode filter unit. The PWM rectifier circuit is the core of the entire system, realizing the conversion of AC power to DC power. Two-way flow. It can also simulate load characteristics and realize switching between states such as lead, lag, rectification, and inversion of grid-connected current and grid voltage. The bidirectional DC/DC converter serves as a DC servo power supply to provide the working voltage desired by the active filter. It works in the BUCK state in the forward direction and in the BOOST state in the reverse direction. The control goal is to make the DC voltage drop of the active filter MOSFET in the subsequent stage as small as possible and reduce the heat generated by this device. Compared with the traditional linear voltage regulator circuit, the voltage drop of this regulator tube is very low (about 0.3V), so the loss is very small and the heat is also very small. This is why this power supply has high power and basically does not need to add a radiator. The active filtering unit further filters the obtained voltage. To be precise here, it is actually mixed-mode filtering. High-frequency noise is filtered out by small differential-mode inductors and capacitors, while mid- and low-frequency noise is filtered by series MOSFETs. The advantage is that very small ripple noise is obtained. At the same time, because the inductance and capacitance of the passive components are small, the dynamic response of the power supply is also very fast. This resolves the conflict between power supply dynamics and ripple. The entire system is independently controlled by two MCUs. The two microcontrollers establish contact through communication, exchange each other's working status, and coordinate work. Achieve smooth switching between grid connection and inverter. 3. Description of the hardware part   Main power topology     MOSFET drive circuit   Drive protection logic   Signal conditioning circuit 1   Signal conditioning circuit 2   Signal conditioning circuit 3   Signal conditioning circuit 4     Signal conditioning circuit 5   Button display and encoder circuit Microcontroller     peripheral circuit 1 (PWM rectifier control)     Microcontroller peripheral circuit 2 (DC/DC and input and output control)   auxiliary power supply 1     auxiliary power supply 2 2. Use words to briefly explain the implementation principle of the work and the working process of the system. Application as experimental power supply: As shown in the figure, when the yellow voltage waveform of the power grid and the red current waveform are in the same phase, it is working in power mode. At this time, energy is extracted from the grid to supply the load. At this time, it is equivalent to a traditional regulated DC power supply, with constant voltage and constant current output characteristics. As can be seen from the red current waveform in the figure, when operating in power mode, the power supply has a PFC (power factor correction) function.    Relevant performance indicators are as follows: AC side input: AC 220V ±20% DC output: 0~25V step value 10mV Output current: 0~3A step value 1mA Voltage display resolution: 10mV Current display resolution: 1mA Voltage control accuracy: 10mV current control accuracy: 1mA Typical output ripple: less than 2mV rms, 10mv pp Power mode full power 50W output as an energy feedback electronic load: As shown in the figure, when the yellow voltage waveform of the power grid is in opposite phase to the red current waveform, it is working under load model. At this time, energy is supplied from the power source under test to the grid. At this time, it is equivalent to a photovoltaic grid-connected inverter, and the input port has constant voltage and constant current input characteristics. As can be seen from the red current waveform in the figure, when operating in load mode, the power supply has a power factor of -1.     Typical values ​​of indicators: AC side input: AC 220V ±20% DC input: 1.0~25V step value 10mV Input current: 0~3A step value 1mA Voltage display resolution: 10mV Current display resolution: 1mA Voltage control accuracy: 10mV Current control accuracy: 1mA Load mode reaches 60W test power Typical output ripple: less than 2mV rms, 10mv pp As an AC electronic load: By cascading two such devices, an AC electronic load can be formed for AC UPS, Loading test of constant frequency generator, etc.; due to time constraints, only one device was debugged and manufactured, and the operation of the AC electronic load was not simulated. In addition, with the popularity of electric vehicles, scrapped batteries will be used for energy storage in the future. Using such a device can help the power grid achieve peak shaving. Earning the difference in electricity bills, isn’t it a bit ahead of its time? Thinking about it makes me a little excited. Of course, the above is just an idea. The most valuable ones at present should be the aging test of the power supply or the automatic charge and discharge test of the battery pack.   4. Material list (BOM list) Core device: ST (STMicroelectronics)/STM32F051c8t6      http://www.szlcsc.com/product/details_10395.html Negative voltage IC ICL7660     http://www.szlcsc.com/product/ details_8358.html TL084CDT            http://www.szlcsc.com/product/details_11677.html Optocoupler           http://www.szlcsc.com/product/details_7114.html Logic device             http://www.szlcsc.com/product /details_6044.html DC-DC chip/MP2451DT         http://www.szlcsc.com/product/details_14780.html 5. Work demonstration Video link: https://v.qq.com/x/page/x0536coaueq.htm l

For more project details, please see the link: http://club.szlcsc.com/article/details_7489_1.html

This project is owned by Lichuang Community "pcs3"