Design Of Pulse Power Supply For Accelerator Based On Floating Topology

During the operation of the pulse power supply,due to the existence of the inductive load,the power supply has a large amount of reactive energy exchanging process during the rising and falling stages of the pulse current.In the rising stage of pulse current,the uncontrolled rectification pre-stage needs to absorb a large amount of reactive energy from the power grid,causing a certain impact on the power grid;while in the falling stage,the feedback reactive energy of the load increases the voltage of DC side,which requires increasing the capacity of the DC side capacitor or consuming it through the braking resistor.In order to improve the beam transmission efficiency of the accelerator device,the pulse current period is required to be shortened sharply,and the current change rate is also changed from hundreds of amperes per second to thousands or tens of thousands of amperes per second.The fast current change rate makes the reactive power required by the power supply larger,and the traditional processing method is no longer suitable.Therefore,in this paper,a new type of suspension topology is studied for the pulsed power supply of the Lanzhou Heavy Ion Accelerator.First,the floating topology is proposed,and its working principle is described in detail.According to the control objective,the design of the control strategy and the derivation of the detailed control algorithm are carried out.Then use Plecs simulation software to simulate the suspension topology,the results show the feasibility of the topology and the correctness of the control algorithm.Secondly,in order to improve the power factor and further optimize the processing of reactive energy by the power supply,it is decided to use a PWM rectifier as the frontend rectifier part of the main module.The model and control strategy of the voltagebased PWM rectifier are deduced in detail,and the PWM wave is generated by the improved SPWM modulation method.The simulation results show that the PWM rectifier further reduces the energy consumption on the grid side and the voltage fluctuation on the DC side of the main module.Finally,according to the power supply design index,a power supply prototype was built and tested with a pulse current of 200 A.The test results show that the floating topology effectively reuses the feedback reactive energy of the load,reducing the impact on the grid side and the bus voltage fluctuation on the DC side of the main module.The bidirectional flow of energy of the PWM rectifier further reduces the influence of reactive energy on the grid side and the DC side of the main module.The floating topology provides a new idea for the design of accelerator pulse power supply.