Research On Harmonic Suppression Strategy Of 400Hz Medium Frequency Aircraft Power Supply

As the important equipment of airport,the high quality and reliable power supply capacity is necessary to medium frequency power supply.As the key part of medium frequency power supply,the output power quality of inverter is directly determined by the control performance.In this paper,the harmonic suppression strategy of 400 Hz medium frequency aircraft power supply is studied and analyzed.The control strategy is optimized and improved based on the theoretical analysis of several traditional control strategies.First of all,a mathematical model is established according to the single-phase inverter topology.The open loop frequency characteristics of the system are analyzed and the active damping strategy with inductive current feedback is chosen to suppress the resonant peak.The double-loop control structure is selected to form a closed loop with the inverter system.Among them,the inductance current feedback with load current is the current inner loop controller,and the output capacitor voltage is the outer loop controller.Due to the fundamental frequency of medium power supply is 400 Hz,the harmonic content is higher than that of industrial frequency power supply so that there are tighter demands in its control strategy.Considering the proportional multi-resonant(PMR)control has good dynamic performance but poor harmonic suppression performance,and the performance of repetitive control(RC)is the opposite to PMR controller,the hybrid control strategy of RC is analyzed.In the analysis of the composite controller,because the outer control loop is voltage loop and the reference input is large,the use of the plug-in RC will cause too much initial overshoot of the system,which is not conducive to the stability of the actual system.Therefore,the application of the repetitive-proportional(PIMR)controller with good dynamic performance and harmonic suppression ability in medium frequency power supply is presented.In addition,on the basis of the internal mode analysis of the PIMR controller,partial sub-harmonic suppression strategy based on the odd RC----the odd proportion multi-resonance(OPMR)controller is proposed.While the mathematical equivalence relationship between the OPMR and the PMR controller is proposed.The proposed OPMR controller not only has the better harmonic suppression characteristics of the PIMR controller,but also has the dynamic performance of the OPMR controller.Finally,the results of simulation by using Matlab/Simulink are presented to prove the feasibility and effective.