1. Previous Power Supply Competition Topics

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1. Previous Power Supply Competition Topics [Copy link]

Analysis of previous power supply competition questions

In the 11th National Undergraduate Electronic Design Competition, there are 10 power supply questions:

• Simple CNC DC Power Supply (1st session, 1994, Topic A)
• DC regulated power supply (3rd session, 1997, Topic A)
• Digitally controlled DC current source (7th session, 2005, Topic F)
• Three-phase sine wave variable frequency power supply (7th session, 2005 G topic)
• Switching Power Supply (8th session, 2007, Topic E, undergraduate group)
• Photovoltaic grid-connected power generation simulation device (9th session, 2009, Topic A, undergraduate group)
• Energy harvesting charger (9th session, 2009, Topic E, undergraduate group)
• Switching power supply module parallel power supply system (10th session, 2011, Topic A, undergraduate group)
• Single-phase AC-DC conversion circuit (11th session, 2013, Topic A, undergraduate group)
• DC regulated power supply and leakage protection device (11th session, 2013, topic L, higher vocational and technical group)

From the previous competition questions, we can see that the "power supply" competition questions range from AC→DC, from DC→AC, from single-phase power to three-phase power, from linear regulators to switching regulators, from single power supply to multiple power supplies in parallel, which have already involved the basics of power supply design and advanced

The most advanced technology is required, and the technical parameters required by the competition are getting higher and higher (for example, accuracy, efficiency η (≥95%), etc.). Example 1: The 2005 G "Three-phase sine wave variable frequency power supply" competition requirements:

1. The output frequency range is 20Hz～100Hz for three-phase symmetrical AC, and the difference between the effective values of each phase voltage is less than 0.5V;
2. When the input voltage is 198V~242V and the load current effective value is 0.5~3A, the output line voltage effective value should be maintained at 36V, and the absolute value of the error is less than 1%;
3. Design and manufacture a circuit that can measure and display the output voltage, current, frequency and power of the variable frequency power supply, with the absolute value of the measurement error less than 5%;
4. When the output frequency of the variable frequency power supply is above 50Hz, the distortion of the output phase voltage is less than 5%;
5. It has over-current protection (acts when the output current effective value reaches 3.6A), load phase loss protection and load asymmetry protection (acts when the difference between any two phases of the three-phase current is greater than 0.5A), and automatically cuts off the input AC power during protection.

Example 2: 2009 A (undergraduate group) "Photovoltaic grid-connected power generation simulation device" competition requirements:

1. With maximum power point tracking (MPPT) function: when RS and RL change within a given range, U Ud = S,
2. The absolute value of the relative deviation is no more than 1%.
3. It has frequency tracking function: when fREF changes within a given range, the frequency fF of uF is made equal to fREF, and the absolute value of the relative deviation is not greater than 1%.
4. The efficiency of the DC-AC converter is such that η ≥ 80% (when RS = RL = 30Ω).
5. It has input undervoltage protection function and output overcurrent protection function.

Example 3: 2011 A (undergraduate group) "Switching power supply module parallel power supply system" competition requirements:

The competition requires the design and production of a parallel power supply system consisting of two 8V DC/DC modules with a rated output power of 16W each. (1) Adjust the load resistance to the rated output power working state, the DC output voltage UO=8.0±0.4V of the power supply system, so that when the load current IO changes between 1.5~3.5A, the output current of the two modules can be automatically distributed in the range of (0.5~2.0) according to the specified ratio, and the absolute value of the relative error of the output current of each module is no more than 2%.

2. Adjust the load resistance to maintain the output voltage UO=8.0±0.4V, so that the sum of the output currents of the two modules IO =4.0A and press

The I1:I2=1:1 mode automatically distributes current, and the absolute value of the relative error of the output current of each module is no more than 2%.

3. Adjust the load resistance to maintain the output voltage UO=8.0±0.4V, so that the sum of the output currents of the two modules IO =1.5A and press

I1:I2= 1:2 mode automatically distributes current, and the absolute value of the relative error of the output current of each module is no more than 5%.

4. It has load short-circuit protection and automatic recovery function, and the protection threshold current is 4.5A (±0.2A deviation is allowed during debugging).

Example 4: 2013 A (Undergraduate Group) "Single-Phase AC-DC Conversion Circuit" Requirements:

Design and make a single-phase AC-DC conversion circuit, with input AC voltage US=24V, output DC voltage UO=36V, output current IO=2A, input side power factor not less than 0.98, AC-DC conversion efficiency not less than 95%.

This content is originally created by EEWORLD forum user Rambo. If you need to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source

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