The Design Of 30kV Adjustable DC Power Supply

DC high voltage power supply is an electronic equipment that takes AC power or three-phase power as the input, the output is tens of thousands of volts DC voltage, it is closely related to the electronic, control and the DC voltage.When make the DC voltage insulation test for electrical equipment, the maximum leakage current through the equipment up to tens of mA, accounting to the transformer capacity is negligible, so the DC voltage test equipment is relatively lightweight, easy to carry to the site of insulation test. DC voltage insulation test has the advantages such as it has little insulation damage to the equipment, the leakage current can be measured simultaneously in the measurement of insulation and it is easy to find the end of the motor insulation leakage. DC insulation test is often used in the detection of power system.The device takes 220V AC as input, through the AC input-rectifier-inverter boost-doubler rectifier to get DC high voltage.First,220V AC comes into the unit by EMI (electromagnetic interference) filter. EMI filtering circuit network can prevent a large number of high-frequency harmonics into the power grid pollution, also can prevent a variety of harmonics into the power rectifier circuit. The device obtains about 300V DC voltage through the full-bridge rectifier. The pulse-width modulation DC/DC links makes DC voltage adjustable. Then the DC voltage is converted into high-frequency AC square wave voltage which will be input to the high frequency high voltage transformer. Finally, the doubler rectifier circuit outputs the required 10-30kV adjustable DC voltage. Feedback voltage is collected by a voltage divider, it is isolated from the control side by isolation amplifier. The feedback voltage will be compared with the given voltage in the UC3842.UC3842 controls the output PWM duty cycle of BUCK converter to achieve voltage regulation. Because the system takes the closed-loop control system, the output voltage can be adjusted timely and effective. The system has over-voltage protection and over-current protection too.The DC voltage power supply output voltage range can achieve 10-30kV continuously adjustable, the output current up to 35mA. The power supply's circuit structure is simply, it is small and easy to use. The DC voltage power supply can be used as a standard equipment in DC insulation test, it has a good application value.