The scheme of large power supply

Release date: 2021/5/11 15:31:55 | Publisher: Shenzhen Cptele Electronics Co., Ltd

 

Introduction to high-power portable energy storage power supply scheme

Portable energy storage power supply is a multi-functional portable AC and DC emergency mobile power supply device, which has a safe shifting lithium-ion battery and inverter conversion technology, and has a "backup power station" with light weight, high capacity and high power. It can provide you with convenient mobile power solutions, which are widely used in mobile office, medical rescue, fire emergency rescue, power equipment repair, environmental land protection, emergency communication support, and on-board storage and backup technical characteristics1. Light weight, small size, easy to carry; 2. AC 220V/110V output; 3 . LED emergency lighting, 24V/12V cigarette light output, 5V-USB output; 4. Lithium-ion battery, safe, reliable and environmentally friendly; 5. With LCD screen display6. High-power PD, QC protocol TYPE-C port output 7. The battery pack is independently protected from overvoltage, overtemperature, overload, overcharge, overdischarge, and short circuit, and the automatic recovery function definition is selected:

1. ACDC input charging power definition, efficiency requirements, whether the voltage is wide, whether it meets the safety design requirements.

2. The battery capacity and series combination mode, as well as the lithium battery protection circuit, and whether the lithium battery (rechargeable type) needs to be protected by equalization technology, are determined by its own characteristics. Because the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short-circuited and ultra-high temperature charged and discharged, the lithium battery components of lithium batteries will always be accompanied by a delicate protection board and a current fuse.

The protection board is composed of electronic circuits, which accurately monitor the voltage of the battery cell and the current of the charging and discharging circuit in the environment of -40°C to +85°C, and control the on/off of the current loop in time. PTC prevents harsh damage to the battery in high-temperature environments.

Balanced charging is the charging method required by all lithium battery packs, but there is actually no balanced charging in many low-power applications, such as most laptop battery packs, the impact on battery life is considerable, and the existing equalization technology is mainly divided into inter-cell energy transfer equalization and external energy input equalization. Cell-to-cell energy balancing is to charge the energy of a high-power battery to a low-battery battery.

The biggest problem with this approach is that it's complicated to control. Many dedicated chip or microcontroller solutions use external equalization through controlled energy consumption. In this method, an energy-dissipating element is used to dissipate energy to wait for other battery cells to fill up or to reduce the voltage of certain cells. The disadvantage of this solution is that the energy consumption on the Zener diode is too high, and the resulting heat generation is intolerable. Another type of switching array in balanced charging is implemented with a power MOSFET.

This method is costly, the circuit is complex, the tubes are working in the switching state, the energy consumption is very small, and the battery does not have a series diode, so the maximum output can be obtained. The disadvantage is that the circuit is more complex, because it needs to match the voltage of each battery, so the input charging circuit is required to be isolated.

3. Whether it has LCD screen or digital tube display, display content: power, voltage, battery capacity, battery life, etc., and the accuracy of power display is required. A fuel gauge chip is connected in series on the protection circuit of the battery, in which an integrated resistor is connected in series, and the resistance value is generally between 20~30 milliohms. The basic principle is that a sampling resistor is integrated into the chip, and when different currents flow through different currents to produce different voltage differences, the chip integrates this voltage (actually converted to current) and time to obtain the correct amount of power for the user to use (note that the unit of power is mAh).

Many chips can achieve this function, and several semiconductor chip companies such as TI and MAXIM have similar products. After the battery adds this chip, the cost increases, and the MCU also puts forward the requirement of "communication". Then, after the chip obtains the capacity through real-time integration, the capacity (in mAh) data is stored in the EEPROM of the chip, and according to the needs of the mobile phone, it is transmitted to the MCU or DSP through the communication line. The memory of the coulomb meter's chip, that is, the fuel gauge chip, usually has the following basic battery information: the initial capacity of the battery (mAh), that is, the rated capacity, the capacity obtained after a battery is fully charged and discharged. The current capacity of the battery (mAh), the capacity of the battery when in use. The current currently flowing through (mA), which is the current consumption of the phone.

4. Whether inverter output is needed and what method to use. Square wave inverter mode, modified wave inverter mode, pure sine wave inverter mode. The square wave inverter mode outputs a poor quality square wave alternating current, and its forward maximum value to negative maximum value is generated almost simultaneously. This has a drastic and unstable effect on the load and the inverter itself. At the same time, its load capacity is poor, only 40%-60% of the rated load, and can not be equipped with inductive loads such as motors, washing machines, refrigerators, relays, fluorescent lamps, etc. If the load is too large, the third harmonic component contained in the square wave current will increase the capacitive current flowing into the load, and in serious cases, the power filter capacitance of the load will be damaged. However, the cost is low, and the output voltage waveform of the modified wave inverter mode is significantly improved compared with the square wave, and the content of higher harmonics is also reduced.

The traditional modified wave inverter is generated by step-by-step superposition of the square wave voltage, which has many problems such as complex control circuits, many power switches used in the superimposed lines, and large volume and weight of the inverter. In recent years, with the rapid development of power electronics technology, PWM pulse width modulation has been widely used to generate modified wave output. The modified wave inverter mode is suitable for the power quality requirements are not very high, and the pure sine wave inverter mode of resistive electrical load outputs the same or even better sine wave alternating current as the power grid we use every day. All in all, pure sine wave inverter provides high-quality alternating current, high efficiency, stable sine wave output, high-frequency technology, small size, light weight, low interference to radios and communication equipment and precision equipment, low noise, and strong load adaptability.

It can drive any kind of load (including TV, LCD, refrigerator and other inductive loads) without interference (e.g. Weng sound and TV noise). However, the technical requirements and costs are relatively high. 5. How many sets of voltage and current are required for DC output, whether the TYPE-C port output of PD and QC protocols is required, and whether the voltage and current need to be customized.

USB Type-C has the following features: The maximum data transfer speed reaches 10Gbit/s, which is also the standard of USB 3.1; The size of the Type-C port socket end is about 8.3mm× 2.5mm slim design; It supports the "front and back plugging" function that can be inserted from both sides, and can withstand 10,000 times of repeated plugging and unplugging; The standard cable with a Type-C connector can deliver up to 100W of power by using 3A of current, and it also supports "USB PD" that exceeds the current USB power supply capacity. At present, most of the PD and QC protocol chips on the market have set the output voltage and current, and due to the non-open software, the customized design has higher requirements for the design ability of the solution company.

 

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