18650 lithium ion battery

　　How to improve the efficiency and maintenance of 18650 lithium ion battery inverter circuit?

　　In order to prevent the lamp from turning black in the early stage, the following technical measures are adopted in this circuit:

　　In order to prevent the lamp from turning black early, the following technical measures are used in this circuit: insert a constant current inductor L1 at the center of the primary winding of the transformer to prevent the current flowing in each cycle from mutating, effectively suppressing the inverter circuit The overshoot current in the lamp reduces the instantaneous overpower phenomenon of the lamp.

　　The forklift 18650 lithium ion battery connects the capacitor C3 in parallel to the primary winding of the transformer to form a parallel resonant tank circuit, which effectively absorbs the peak voltage on the primary winding and prevents excessive consumption of electrode material for the lamp. Adding a cathode heating winding NK can improve the starting characteristics at low temperature and low voltage, and can also reduce the ignition voltage required for the lamp.

　　In order to improve the efficiency of the inverter circuit, the ratio of the transformer magnetizing current Im to the collector load current IR should be small. However, reducing the transformer magnetizing current requires the primary winding to have a higher inductance, which will increase the size of the transformer.

　　Therefore, the efficiency of the inverter circuit and the size of the transformer must be properly considered. Usually, the magnetizing current Im is controlled at about 15% of the load current iR. During design, it is difficult to accurately select the HS value because the HS value is related to both the properties of the magnetic material and the method of assembling the core. It is best to use experimental methods to measure the HS value, and then determine the HS value of this material based on the efficiency of the inverter circuit.

　　Repeat the measurement several times to obtain the best value. The number of turns Nb of the feedback winding is given by the following formula: Nb=NPUbUi. In the formula, Ub is the required voltage on the base winding. In the calculation, first set Ub=114V or so, and then according to the temperature rise of the power tube, Make appropriate corrections to minimize the temperature rise of Q1 and Q2. For different transistors, the value of Ub is also different. The basic principles for selecting transistors are that the switching speed should be fast, the saturation voltage drop should be small, and the collector current should be large.

　　In addition, the power capacity and withstand voltage requirements of the power transistor are also very important. C-E junction reverse breakdown voltage of the transistor BVCEO3Ui Maximum current of the transistor collector ICM3Icpk Rated power consumption of the transistor PCM23P0 In addition to the above requirements for power transistors, another important indicator is the secondary breakdown withstand capacity. In particular, power transistors whose bases are turned off under reverse bias are more susceptible to secondary breakdown and must be noted.

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