The Design Of The Bipolar Pulse Plating Power Supply

Plating goods is widely used in our daily life. With the demand of the marketdevelopment in recent years, people have a higher demand in overall appearance, the qualityof the coating, gloss and the uniformity of the plating goods. The power is the energy providerof the plating process which is a low-voltage and high-current device. A simple operation ofthe power is required in plating, and the power can withstand the mutations of input variousconditions, output overload, short circuit and other issuses impact. The DC electroplatingpower supply has been widely used in the electroplating industry for a long time, but with theever-increasing demands of electroplating, the pulse electroplating power supply appeared.Compared to DC plating, pulse plating has a lot of excellent performance. Pulse platinggoods have high quality, thin coating, high production efficiency, and detailed crystallization.The electrodeposition process of the metal ions can be chaged by adjusting the outputvoltage’s frequency, duty cycle and other parameters, thereby the coating physical andchemical performance are improved, at the same time the precious metals are saved. Theworking principle of the pulse plating is detailed elaborated in the thesis. The design ofbipolar pulse electroplating power supply is proposed. The design of the power main circuit isdeeply discussed. The software and hardware design of the control section are deeplydiscussed.In this paper, the design of the main circuit includes the three-phase rectifier circuit part,the DC/DC converter and the pulse output section. The three-phase rectifier uses anuncontrolled rectifier; the two DC/DC converters whose outputs are positive and negative lowvoltage and high current respectively are designed to export positive and negative bipolarpulse. As a high power electronic device, the IGBT is used in the improved phase-shiftedfull-bridge ZVS PWM DC/DC chopper, and the IGBT is gived a soft shutdown, reducing theloss of the circuit. The EE130core is selected and the transformer is made according to thecalculated parameters results. The low-voltage high-current output signal of the transformer isfull-waved rectified. The rectifier can be achieved by selecting the schottky diode as the rectifier component. Synchronous rectification approach is recommended to be used to furtherreduce the circuit losses and improve efficiency; two sets of the MOSFET which have verylow on-state resistance and allow high current to flow through are used as a switching devicein the pulse output section, and they can be controlled to form positive and negative pulses.The UC3875is used as the core of the phase shift control in the DC/DC chopper controlsystem. The IGBT driving circuit is designed. The C8051F020is used as the control core ofthe MCU control system, which is mainly used to display the circuit voltage and the current,set the parameters of the output pulses and display the parameters and control the high powerelectronic switchs to form bipolar pulse.According to the working environment of the electroplating power and the operatingstatus of the circuit, some protection circuits including overcurrent protection, overvoltageprotection and overtemperature protection are designed. Some anti-jamming measures ofsoftware and hardware are proposed. The manner of air cooling is used to distribute the powerheat to make the electroplating power operate normally and reliably.