The Research On Low-voltage And Large-current High Frequency Switching Power Supply Used For Electrolytic Plating

Based on a project for the traditional rectifier power supply technicaltransformation of a Hefei copper limited liability company, a low-voltage andlarge-current efficient energy saving electrolytic plating high frequency switchingpower supply which is applicable to low voltage distribution network is researched inthis paper. By applying PWM rectification technology to switching power supply, itgreatly reduces the harmonic content of grid-side current and then improves its powerfactor, realizing the efficient utilization of energy and saving the cost. This papermainly consists of following parts:Firstly, the topology and working principles of traditional large power rectifierpower supply is analyzed. Its structure generally has two levels: the pre-stage rectifiercircuit and the post-stage DC/DC converter circuit. The main problems of thetraditional rectifier power supply are summarized in this paper by analyzing thedistortion rate of grid-side current and power factor. After that, a novel topology ofrectifier power supply is presented, whose pre-stage circuit is PWM rectifier andwhose post-stage circuit is full-bridge DC/DC converter. The working principles ofthe pre-stage and post-stage circuit are described in details and the mathematicalmodel is established.Secendly, the control strategy of the low-voltage and large-current electrolyticplating high frequency switching power supply is discussed in this paper. A compositecurrent deadbeat control method based on power feed-forward for the pre-stage PWMrectifier of the high frequency switching power supply is proposed, realizing thereal-time track of the load power; for the post-stage full-bridge DC/DC converter, adouble closed-loop control strategy of current out loop and voltage inner loop isproposed to achieve output of the converter with low ripple. The correctness andvalidity of the proposed control method are verified by simulation. The stabilityanalysis of the proposed control strategy is also carried on in this paper and the resultsshow that the control strategy has good stability. To solve the multi-parallel problemof switching power supplies, a current-sharing control method based on virtualresistor is discussed in this paper, which can improve the output characteristic of theswitching power supply from control and achieve the current-sharing control ofmulti-parallel switching power supplies. Thirdly, a low-voltage and large-current efficient energy saving high frequencyswitching power supply with160kW power is designed in this paper. The detaileddesign scheme of the hardware and control system is put forward, and the actualapplication effect of the device is also given. The results show that the novel efficientenergy saving switching power supply has several advantages such as low distortionof input current、pollution-free、high power factor and high energy utilization rate, etc.Based on the large harmonic current and low efficiency in the traditionalelectrochemistry rectification power supply, this paper studies the topology structureand control technology of low-voltage and large-current electrolytic plating highfrequency switching power supply. In combination with engineering examples, thepaper proposes the design methods of hardware and software in details. The researchcontents of this paper can provide draw lessons from and reference for traditionalrectifier power supply technical transformation.