| Aeronautical Static Inverter(ASI) is a kind of static converting device, which converts the DC(27V/270V) in the main power of aircraft into AC of constant-voltage and constant frequency by means of power semiconductor devices. With the development of the aircraft, all the electric equipment on the plane requires the power supply system with better performance. The Rotational Converter could not satisfy with the requirement anymore. Compared with the Rotational Converter, ASI is better in the efficiency, power density, reliability and electrical quality. ASI have already replaced the Rotational Converter in western developed countries since the 70's. But, in our country, most acitive aircrafts are still using Rotational Converters as the secondary power supplies. So it is urgent for us to develop our own ASI.The mam purpose of this dissertation is to achieve high power density, efficiency, reliability and electric quality of ASI. The novel Forward DC Link Inverter, made up by a DC/DC converter, an energy storage circuit and an inverter, has been chosen because of its advantages of simple structure, high-frequency isolation function and easy achievement of modular design.Because of the advantages of high efficiency, small volume and weight, the active-clamped forward circuit are used as the DC/DC converter. The DC/DC converter provides pulse voltage, which returns to zero periodically, for the devices in the inverter to realize ZVS. But the devices still have some on-loss under two kinds of state commutation. Therefore, it is better to use the devices with smaller junction capacitor.The selection rule of the hysteresis width has been developed in order to make the THD and RMS value of the output voltage to be the best with high efficiency, according to the principle of pulse density modulation. The equation of selecting filter capacitor is derived to make the feedback energy which is produced by the inverter to be minimum. The value of the capacitor has been decreased from 20u.F to 7.6fiF and the efficiency has been improved by 1.5%. The maximal filter inductor value has been given on the base of the hysteresis control principle. The minimum filter inductor value is also given to limit the maximal pulsating inductor current. Both the simulation and experimental results show that the design method is feasible. The value of the inductor has been decreased from ImH to 0.65mH. Then the volume and weight of the system could also be reduced.The loss analysis shows that the main loss is the loss of primary loop so the effectiveapproach of improving efficiency is to lower the RMS value of primary current. Two novelcontrol schemes are proposed in this paper. The first one improved efficiency by 2.5%. The efficiency has been increased 0.42-0.96% by the second scheme.On the base of the research result mentioned above, a novel three-phase combined ASI is proposed hi this paper, which is made up by three single-phase ASI. Each single-phase ASI works separately. Thus modular design can be realized conveniently. The analysis shows that it has good performance even with unsymmetrical load.A single-phase prototype of 27VDC/115V(400Hz)/lKVA and a three-phase prototype of 27VDC/115V(400Hz)/3KVA have been developed successfully according to the research result mentioned above. The experimental results show that they have good performance.
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