The Design Of The Frequency Converter With High Performance Switching Power Supply

The inverter consists of the rectifier circuit, the inverter circuit, the driving circuit, the switching power supply circuit, the control board circuit and filtering amplifier circuit Switching power supply is controlled by the PWM pulse turn-on and turn-off of the MOSFET in order to maintain a stable output voltage.The design of switching power supply is one of the core of the design of inverter hardware, which provides operating voltage of the control system and driver circuit chip.Its performance has a direct impact on the overall performance of the variable speed system.This thesis mainly studies around flyback switching power supply with multiple outputs used in the inverter,and focuses on the research of the design,test,simulation and debugging of the switching power supply.The main contents are as the following:In the beginning of the thesis describes the working principle of the inverter.suming up the advantages of switching power supply used in the inverter and how to get DC voltage. And then dictates requests about output voltages,ripple and so on of the switching power supply designed in this thesis.Then discusses the working principle of the flyback converter topology and analyses of the key technology in the design process.such as the transformer.RCD clamp circuit.feedback loop and so on.Then simply analyses of why choose flyback topology and select UC3842.On the basis of the theoretical analysis.then starts the designs of the UC3842peripheral circuit.transformer.start-up circuit.RCD circuit.output circuit.feedback circuit.schematic and PCB layout.Finally tests the switching power supply when the inverter is running.including the output voltage.ripple.the drive waveform.EMI conduction.radiation and temperature rise.If the result does not meet the requirements then use SIMetrix simulation analyses the reasons and take effective actions to meet the indicators.Duing to the limitations of laboratory equipment.some waveforms or informations can not be tested.such as the dynamic load characteristics.only verify through SIMetrix simulation.The results of the simulation and experiment show that the indicators of the switching power supply meet the requirements when the inverter is running.proving the feasibility of this design and consistent with the theoretical analysis.