Development Of IPOS High Voltage DC Power Supply

With the continuous progress of society and the rapid development of science and technology,high-voltage DC power supply is widely applied in all walks of life,and people's demand for its performance is also gradually improving.The current high voltage DC power supply has the advantages of small volume,high efficiency and fast adjustment period.But when the output voltage is high and the power tube is under low switching stress,the single DC power supply can not meet the requirements obviously.The series and parallel combination of multiple power modules can solve this problem well.A IPOS(Input-Parallel Output-Series)high frequency and high voltage DC power supply is designed to meet the requirement of a ship equipment.The power supply which is combined of multi DC power supply is realized by the parallel connection of the input terminal and series connection of the output terminal.The main technical specifications of the single module are: DC input of 50-100 V,high voltage DC output 5-15 kV,maximum output power of 2.5 kW,and over current and over voltage protection function.The main circuit topology of IPOS high frequency and high voltage DC power supply is presented in this paper.The high frequency inverter resonant circuit is analyzed.The selection of IGBT is completed through calculation.The steady-state modeling and small signal analysis of the LCC resonant circuit are carried out.The specific steps to determine the parameters of the LCC resonance are obtained.The key analysis and design of the high frequency and high voltage transformer is given.Through the simplified model,the type selection and loss calculation of the core are completed.According to the actual parameters,the number of sections,the number of layers and the number of coils in each layer are calculated under different voltage levels.The Z type winding mode is selected by contrast and analysis,in order to reduce the distribution capacitance of the transformer,increase the insulation strength and the heat dissipation capacity of the whole system.The small signal model of the combined system is analyzed,and the corresponding transfer function is defined.Through the decoupling analysis of the small signal model,the gain of the total output voltage and every output voltage close loop is obtained.The PI regulator is designed and analyzed.The model of the system is built by Matlab and the software and hardware design department is built.The control circuit based on dsPIC33 F digital signal controller is introduced.The design and debugging of AD sampling circuit,PWM(Pulse Width Modulation)circuit,over-voltage over-current protection circuit and other hardware circuits are completed.The real-time sampling of voltage and current waveforms at various key points of the system has been produced,and the PWM drive waveform is produced too.The software and hardware protection of over-voltage over-current failure and the stability of output voltage and voltage of each module are realized through the control of PI.Finally,a prototype of IPOS high voltage DC power supply is made to verify and test the theory.The correctness of the topology design and control formula of the power supply is finally proved by the experiment.