Design Of Pulse Power Supply Based On Lcc Resonant Converter

With the development of science and technology,the requirements of different load types for power supply are increased.The digital power supply with high frequency and high power density is the development tendency.The LCC series-parallel resonant converter is a typical topology applied to a high-voltage DC power supply.By using a distributed capacitor to achieve soft switching under full load conditions,the power efficiency of the converter is improved.However,its amplitude-frequency characteristics are affected by the switching frequency and load size.Under a wide operating range,the switching frequency varies greatly,and it is difficult to obtain a good dynamic response,especially in the case of wide gain and large load variation.The LCC resonant converter has a slow dynamic response,low steady-state accuracy,and unstable output voltage.In this paper,the LCC resonant converter is studied in combination with the characteristics of pulsed power supply.The specific contents include:In order to get the circuit characteristics of LCC resonant converter,the extended fundamental harmonic analysis method is used to analyze the current continuous mode under variable frequency modulation.The steady-state equivalent circuit of LCC resonant converter is established.Circuit characteristics such as voltage gain,input impedance,resonant current,and wide-range output are discussed.Based on the analysis above,the different working areas and soft-switching characteristics of traditional variable-frequency modulation and fixed-frequency phaseshift modulation are analyzed.The variable-frequency and phase-shift hybrid modulation is used to reduce the frequency adjustment range.A design method for the constraint law of hybrid modulation between phase shift angle and switching frequency is obtained.Simulation verification in plecs proves that a wide range of outputs can be achieved in a narrow switching frequency range and soft switching conditions are guaranteedFor the pulsed power load sudden change condition,the traditional linear compensation controller is difficult to adapt to the full range output.In this paper,the trajectory control is used to improve the dynamic response during the load switching process,and the state variable plane is used for accurate time domain modeling.Electrical stress of resonant tank is carried out.Based on the analysis above,the state variable trajectory is drawn,and the time optimal transient process trajectory between different configurations and configurations is analyzed.The experimental platform of LCC resonant converter based on DSP is designed.The circuit parameters and transformer are designed according to the power performance index,and the influence of the parasitic parameters of the transformer on the circuit is analyzed.The software control scheme is designed to verify the hybrid modulation and trajectory control.The comparison experiment proves that the PI with trajectory hybrid control has better dynamic characteristics,and the experimental results basically reach the expected design index.