Research On Digital Full-bridge Dual Buck Inverter

Aeronautical Static Inverter(ASI)converts the generator or battery power to constant voltage and constant frequency AC power.ASIs provide high quality power for critical equipments on the plane,and they are the important parts of the power supply system.In this paper,we study the problem of how to improve the efficiency of the converter,improve the quality of the output waveform and reduce the short circuit loss of the full digital double Buck bridge inverter.Dual Buck full bridge inverter(DBFBI)based on carrier phase shifted SPWM(CPS-SPWM)is used in aeronautical static inverter.When the output voltage is close to the input voltage,the output duty cycle of SPWM is close to 1.In this paper,it is proposed that the switching frequency of the inverter can be reduced when the inductor current ripple is small.The switching loss of the inverter is reduced without affecting the stability of the controller and the quality of the output waveform.In order to solve the problem that the output voltage of the double Buck full bridge inverter has zero crossing distortion,this paper proposes a control method which can eliminate the zero crossing distortion and reduces the output voltage waveform of the inverter THD.The additional loss caused by the change of the control method is analyzed,and the design method of the parameters is given.In order to solve the problem of redundancy in digital control system,this paper presents a method to quantitatively analyze the errors caused by the numerical calculation.The optimization method of circuit control program is designed,which can achieve very fast operation efficiency.The standard requires that the aviation static inverter can output three times rated current in the short circuit state,and at least 5S.Short circuit power device switching loss,easy to cause damage to the inverter.This paper analyzes the short circuit loss,control method is proposed to maintain output short circuits in some time during the opening of the switch tube,greatly reduces the switching loss of the inverter circuit,the simulation and experimental verification.A 1kVA inverter is developed,and the correctness of the theoretical analysis is verified by experiments.