Working principle of electric cars’ chargers

220v AC power is suppressed by T0 bidirectional filtering, D1 rectification is pulsating DC, and then C11 filtering forms a stable DC current of about 300V. U1 is a TL3842 pulse width modulation integrated circuit. The 5 pin is the negative pole of the power supply, the 7 pin is the positive pole of the power supply, the 6 pin is the pulse output and the FET Q1 (K1358) is directly driven. The 3 pin is the maximum current limit. Adjusting the resistance of R25 (2.5 ohm) can adjust the maximum current of the charger. . The electric vehicle charger schematic diagram 2 is the voltage feedback, which can adjust the output voltage of the charger. The 4-pin externally connects the oscillating resistor R1 and the oscillating capacitor C1. T1 is a high frequency pulse transformer with three functions.

The first is to press the high voltage pulse into a low voltage pulse.

The second is to isolate the high voltage to prevent electric shock.

The third is to provide working power for uc3842. D4 is a high-frequency rectifier tube (16A60V) C10 is a low-voltage filter capacitor, D5 is a 12V Zener diode, U3 (TL431) is a precision reference voltage source, with U2 (optocoupler 4N35) to automatically adjust the charger voltage. Adjust w2 (fine tuning resistor) to fine tune the charger voltage. D10 is the power indicator. D6 is the charging indicator.

R27 is the current sampling resistor (0.1 ohm, 5w). Change the resistance of W1. Adjust the inflection point current of the charger to float. Electric motor charger schematic (200-300 mA). At the beginning of power-on, there is about 300v on C11. This voltage is loaded all the way to Q1 via T1.

The second pass through R5, C8, C3, reaches the 7th foot of U1. Force U1 to start. U1’s 6-pin output square wave pulse, Q1 works, and current flows through R25 to ground. At the same time, the T1 secondary coil generates an induced voltage, and through D3, R12 provides reliable power to U1. The voltage of the T1 output coil is rectified and filtered by D4 and C10 to obtain a stable voltage.