Select the battery model of the load
We first discuss the two must be considered, but eventually gave up modeling method. One of the ways the battery dell laptop battery load modeling are: the use of a source out (discharge) and inhalation (charge) current capacity of the battery voltage source and internal resistance of the resistor in series. As the Li + batteries require precise control of the termination voltage and charge current, present, all Li + battery charger is actually regulated power supply converters.
In addition, regulated power supply converter (charger) depends on the stability of the load (battery) the dynamic characteristics, we must select a model very similar to the load. Otherwise, the test can only verify that the VI characteristics of its own charger.
If only a one-off test, you can use the shunt regulator and resistor in series, This is enough to simulate the battery internal resistance, and, this simple cell model for fully meet test requirements. Advantage of this approach is powered by the charger itself. However, Laptop Battery a more rigorous testing needs of more accurate models. The model uses internal voltage source, voltage value is the process of charging the battery supply, a function of the total charge.
With the constant current source to charge the battery when the voltage will continue to change to a certain increase in positive slope. This is due to the internal battery discharge and other chemical changes in the process, accumulate around the cathode polarization of ions gradually reduced. Therefore, the operating point depends on the battery charger to connect the length of time, and the battery work history. Most E-Lab can be found using common components to build the load, to simulate the load of this complex model is difficult.
Require frequent testing of the charging circuit, or circuit characteristics must be described in detail, accurate simulation of the process of charging the battery dell Inspiron 2000 battery is very useful. Simulation process requires continuous scanning of all dc operating point charger. Analog circuits but also display the results, so that the operator can identify the problems and failures and interference. If the analog circuit can provide the battery voltage output and signal, these results can be directly as the oscilloscope signal. Testing can be speeded up (from hours to tens of seconds), and can be repeated many times as needed, than with a real battery test more convenient. However, after accelerated testing to determine the thermal effect of the negative charging power supply. Therefore, the test may require additional time to work with rechargeable power supply and adjust the thermal time constant of the circuit coincide.
The establishment of the battery model of the load
Figure 2 circuit simulation is the single-cell lithium-ion batteries. CC Stage charger termination charge voltage and fast charge current from the charger setting. Simulator is initialized, it can set the internal battery fully discharge voltage under the conditions of 3V,dell W0465 battery but the voltage can be raised to 4.3V, in order to test the situation before charging. 3V initial value is typically used low-battery voltage shutdown circuit (used to terminate the lithium-ion battery discharge process). This design specifically for the termination of charging voltage for the 4.2V standard CC-CV lithium-ion battery charger. The design of adjustment is very easy to adapt to non-standard termination voltage and fully discharge voltage tests. Test charger up to 3A charge current drive emulation circuit, by the power transistor power limit. Figure 2 circuit to simulate the increase in battery voltage, battery voltage is from a simulation of the circuit is set to begin fully discharged state, the circuit charging current function.
Figure 2 a single Li + battery case simulation circuit, the circuit can not use the actual situation of the battery to test Li + Battery Charger
According to the figure given in the parameter values, the charge current is 1A, the integration time constant of the analog circuits within 6-7 seconds dell Latitude X300 battery to reach 4.2V charger restrictions. On the current range, resistance, charge termination voltage and discharge voltage of the simulation is complete in the lithium-ion battery (in this case middle finger Sony US18650G3) typically done on the basis of the parameters. The simulation of the battery voltage without considering the impact of ambient temperature.
Shunt regulator design uses a MAX8515 shunt regulator and a pair of bipolar power transistor (select the regulator to take into account its internal reference voltage accuracy), high current TIP35 transistor installed in the radiator to dissipate 25W of heat on.
MAX4163 dual op amp which an amplifier is used to charge current integration, and the other amplifier on the current measurement signal amplification and bias. The op-amp has a high power supply rejection ratio, and supports full-swing input / output range of the two functions to simplify dell BAT3151L8 battery the circuit design. Note that, with the battery positive terminal emulator 0.100Ω current-sense resistor in series as well as the battery internal resistance.
In the automatic testing - data acquisition functions within the system work, can be an external signal to reset the simulation of the battery to fully discharge state. In addition, the manual operation test settings, reset button can be used.
The use of single-pole single-throw switch can choose two kinds of simulation of battery operation. To throw A-side, the realization of integral charge emulator, as described above. Throw B-side, the simulator will be set at a fixed dc operating point of the charger on-site testing of the output voltage and current smoking. To achieve this functionality, "Settings" voltage by changing the 50kΩ variable resistor, in the manual adjustment of between 2.75V to 5.75V. These settings are voltage internal inhaled current. The measured voltage terminal emulator (VBATT) is equal to set the voltage current flowing through the simulation cell with suction resistance (0.100Ω resistance) produced by pressure drop. Simulation circuit when the power from the battery charger dell 1G222 battery output.
Simulation of circuit performance
Figure 3 for the simulation of lithium-ion batteries to a 4.2V waveforms obtained in a typical VI. As can be seen from Figure 2 in the testing process: an initial fast charge current is 1A Charge (curve B and D), the other is a 2A fast charge current charge (curve A and C). In both cases, the first phase into the CC charge until the battery voltage reaches the termination voltage of 4.2V. After that, the current exponential decay, while the simulation of the battery voltage remains unchanged. Charge current is 2A, the time required to reach the termination voltage is shorter, and is expected to design the same. However, please note, the current double charging time does not make half will only make the time to reach half the CV mode, the battery load test with the real case.
Figure 3 according to Figure 2 battery simulation circuits dell INSPIRON 2650 battery draw graphics, fast charging waveform showed that the two conditions, the battery charger work, namely: CC phase 1A (curves B and D) and 2A (curves A and C) Charge Current
Figure 4 is set for two different voltages: 3V and 4.1V when the VI curve of absorption current. Two curves of dynamic resistance (indicated by the slope) is only simulated by the battery internal resistance 0.100Ω resistance.
Figure 4 Figure 2 circuit at a voltage of 4.1V (upper curve) and 3V (lower curve) when inhaled current two cases are representative of the slope resistance 0.1Ω
Conclusion
As the lithium-ion battery charging process takes one hour or longer, using the actual load test lithium battery charger would be very time-consuming and often impractical. In order to speed up the battery charger testing, this article describes a simple circuit, used to simulate the lithium-ion battery. The circuit provides a non-use of the actual battery lithium battery dell INSPIRON 2600 battery charger to test effective means of
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