Research On High-reliability High-power Electroplating Power Supply

Electroplate power supply based on the technology of switching power supply has been widely applied in electroplating industry because of its excellent performance. With the development of computer, micro electronics and power electronics, electroplating power supply with low voltage and high current output characteristics has become a hot topic. Domestic and foreign scholars have conducted the thorough research on the methods to improve the switching frequency, power, power efficiency, electromagnetic compatibility and reliability. This paper studied the reliability design of the electroplating power from the basis, including reliable circuit topology structure, reliable and efficient power adjustment control mode, safety protection measures with redundant, components and circuit anti-interference design. This paper also studied the method to improve power efficiency.The design of the main circuit is composed of half bridge topology, the annular magnetic core transformer and parallel full wave rectifier output structure. Half bridge topology has the characteristics of simple structure, moderate output power, ability of anti magnetic flux imbalance. Ring core transformer has the characteristics of low EMI, low temperature rise. The main circuit has achieved the fundamental reliability. In order to balance the control reliability and control sensitivity, the design uses double closed-loop control mode which can limit and adjust the output current per period. This paper analyses the model of double loop control system, eliminates the condition-stable phenomenon, designs appropriate parameter to ensure the stability of the control loop. Double loop controller alone with and mature and reliable PWM drive chip constitutes the power adjustment of the power supply system design. In order to ensure the reliable operation of power system, this paper has designed multiple protective measures, including switch tube driving with self turn off capability when having a fault, independent external monitoring and protection circuit based on FPGA, design, serial communication for remote monitoring of operating parameters, friendly man-machine interface which can preserve the fault state of machine. According to the relatively poor working environment, this design uses optimized circuit, strong anti-jamming capability components and derating design in order to ensure the reliability of the circuit. At the same time, in order to enhance the efficiency of electroplating power supply, this paper adopts synchronous rectification technology and simple parallel output structure.In order to verify the design scheme, this paper made a prototype system which has 5~12V adjustable output voltage and 200 A maximum output current. Then the output characteristics, double loop control characteristics, security and remote communication capability of the prototype system are tested. The results show that, the prototype achieved design requirements with high reliability and operating efficiency. So this design scheme in this paper has a certain application value for the electroplating industry.