ZERO-CURRENT AND ZERO-VOLTAGE SWITCHING PWM BOOST FULL-BRIDGE CON VERTER

This paper proposes a zer o current and zero voltage switching (ZCZVS) PWM Boost full bridge (FB) conve rter. With series inductors, the leading switches can realize zero current swit ching (ZCS) in a wide load range using the energy of the output capacitor. Ma king use of parasitic capacitors of the lagging switches and parallel auxiliary i nductance with the primary winding of the transformer, the lagging switches can realize zero voltage switching (ZVS) under any load. Compared with the ZCS PWM Boost FB converter, the new converter has no current duty cycle loss. Operat ional principle and parameter design are analyzed. Experimental results verify the effectiveness of the proposed converter.

Design and performance of an EMI filter to reduce conducted EMI in an isolated full bridge buck converter power supply

EMI Filter Design and Performance for isolated full bridge buck converter is developed in this paper. In order to design a high performance EMI filter, many issues need to be considered beforehand. Some important issues including accurate model of converter components, parasitic elements, its effect on EMI noise and impedance mismatch are included in this paper. A numerical prediction of EMI/EMC has the potential to evaluate EMI performances at the design stage and before prototyping. It can also help reduce the post-prototype EMC cost by minimizing late redesign and modifications of a design implementation. Saber simulator is used to analyze the EMI noises and EMI filter’s performance. Conducted EMI noise measurement and EMI filter design of isolated full bridge buck converter has been achieved while successfully satisfying the FCC class B limits in the frequency range from 150 kHz to 30 MHz. Simulation results are compared with experimental data and the effectiveness of the EMI simulation approach is demonstrated.

Improved Full Bridge Converter with Low Peak Voltage on Rectifier Diodes

To suppress peak voltage on rectifier diodes in a full bridge( FB) converter,the mechanism of peak voltage was analyzed and an improved FB converter was proposed. One reason for peak voltage is the resonance of the transformer's leakage inductance and the rectifier diodes' junction capacitances. The other reason is that the fast reverse recovery current of the rectifier diodes flows through the transformer's leakage inductance. An H bridge composed of four diodes,an auxiliary inductance, and a clamping winding were adopted in the proposed converter,and peak voltage was suppressed by varying the equivalent inductance, principally in different operating modes. Experimental results demonstrate that the peak voltage of rectifier diodes decreases by 43%,the auxiliary circuit does not lead to additional loss, and the rising rate, resonant frequency,and amplitude of the rectifier diodes' voltage decrease.Peak voltage and electromagnetic interference( EMI) of rectifier diodes are suppressed.

Design and development of strip electrode power supply for HEPS wiggler

Purpose The high-energy photon source(HEPS)is the first fourth-generation synchrotron photon source in China(Jiang et al.in Sci Sin Phys Mech Astron 44:1075-1094,2014).The strip electrode and its power supply provide necessary hardware support for correcting the magnetic field of the wiggler as reported by Zhao and Yin(Particle accelerator technology,Higher Education Press,Beijing,2006).The design of the conventional power supply for accelerators,with a large output current and high output voltage,making it easy to achieve high stability of the output current.The strip electrode power supply poses difficulties in achieving high stability due to its small output current and voltage.Because of size limitations,as well as the requirements of the power architecture,there are currently no commercial products for this type of power supply.Methods Designed and developed 32 strip electrode power supplies.Considering the large number of power supplies and limited space,a rack structure design was adopted,placing all power supplies in one rack.The main circuit of the power supply adopts a full bridge transformation structure(Chao et al.in Radiat Detect Technol Methods 6:470-478,2022),and the control scheme adopts full digital control based on FPGA(Long and Cheng in At Energy Sci Technol 43:780-784,2009).The power supply has two control modes:local operation and remote operation as reported by Lu(Particle accelerator technology,Hunan University,Changsha,2010).Results The test shows that all power supplies meet the indicator requirements,with a stability of less than 100 ppm.Conclusions The strip electrode power supply can effectively correct the multipole integral field error and improve the integral field performance of the wiggler.