Research On Wide Output And High Efficiency Anode Power Supply Of Low Power Hall Effect Thrusters

Hall effect thrusters(HET)have the advantages of small size,high specific impulse and flexible adjustment of thrust.The nano-and micro-satellites equipped with low power HET can perform tasks such as orbit maintenance,precise position adjustment and no-drag control.However,the former topology scheme of the anode power supply(APS)of the HET power processing unit is not suitable for low power applications.Aiming at the application of low power HET and the requirements for propulsion performance,this dissertation proposes an APS which has the features such as wide power range,wide output range,high efficiency and fast dynamic response.The research is mainly carried out from the analysis and selection of topological schemes,research and design of main circuit parameters,analysis of closed-loop control performance and reliability,and optimization of prototype.Aiming at the requirements of the low power HET,the APS should have wide output range and high efficiency,then an active clamp forward/flyback topology APS scheme is adopted.The working principle of the topology is analyzed,and the phase shifted full bridge topology parameters are designed,which is the traditional scheme.The soft switching conditions and voltage gain range of these two schemes are experimentally verified.By comparing and analyzing the performance,advantages and disadvantages of these two schemes under the technical requirements in this dissertation,it is verified that the new scheme is more suitable as the APS topology scheme.A utility method of converter parameter design is adopted in order to achieve a wide voltage gain range of the APS.A detailed steady-state analysis of the active clamp forward/flyback resonance topology is carried out.The derivation of the circuit during steady-state is provided.The correctness of the derivation is verified.Soft switching conditions and duty cycle limit conditions are introduced.The influence of secondary resonance parameters on voltage gain range and efficiency as well as the clamp capacitance on the secondary discharge time is discussed.Then the converter parameters design is completed.The APS system compensation network is designed to ensure the stability and flexibility of the HET.The frequency characteristics under different working conditions are analyzed.The shortcomings that low frequency gain is insufficient and crossing frequency is low are solved by designing a compensator.The converter achieves fast dynamic response when the input bus voltage,target output voltage or load hops.Besides,the converter can ensure the system stability and target output range when the topology parameters drift to some extent.A prototype is built to verify the actual performance of the converter.The soft switching performance,output voltage range,load regulation rate and efficiency are tested.The prototype meets the design requirements.The converter can realize soft switching in the entire voltage gain range and load range.The output can be flexibly adjusted within the full range of the input voltage.The target voltage gain range,high efficiency and low load regulation rate are achieved.The loss distribution of the converter is analyzed for the further improvement of the system efficiency.