Design Of Indoor High-voltage Power Supply For Air-cleaners

As the development of industrialization in our country, the air pollution is getting serious, the indoor air purification is getting the attention, the negative ions air cleaner is used widely. Recent years, the advanced design of high voltage power supply of negative ions air cleaner become the hot spot. The power supplies of negative air cleaner are moving toward miniaturization, portability and high frequency, but there are some shortcomings including complicated design of circuit, higher switching power loss, low efficiency, unstable output. Therefore, how to design a high voltage power supply with simple circuit topology structure, less cost, low switching power loss is the core of this study. The designed power supply is with input voltage 220V/50Hz,switch frequency 20kHz, power factor more than 0.95, efficiency more than 85%, rated power 10W, Ripple coefficient is less than 5%,output DC high voltage-lOkVThe high voltage power supply uses the switching power supply technology, PFC circuit, PWM control technology, active clamp flyback inverter technology and ZVZCS soft switch technology. The designed EMI filter can filter out the high frequency interfering signal and noise; The Two stage Valley Fill circuit can improve the power factor of power supply; The power supply uses active clamp ZVZCS flyback converter main circuit. According to the study, It proves that switch tubes are opened with zero voltage and commutation diode is shut off with zero current, clamp capacitance can inhibit the peak voltage of switch tubes. So the power switch loss and circuit complex problems are solved; At the same time, design the control circuit with PWM control chip SG3525,the drive circuit with TLP250 optocoupler, protection circuit and multiple rectifier, which realize good effects about the simple circuit design, low cost, easy to design and electrical isolation; Finally, the design process of power transformer is introduced and analysed in detail. Finally,the power supply is accomplished as expected with miniaturization, low loss, stable output, output voltage-10kV, power 10W,switch frequency 20kHz.