Design and Demonstration of High Power Density Inverter for Aircraft Applications
Abstract
This paper presents a design methodology for high power density converter (HPDC), which emphasizes on weight minimization. The design methodology considers various inverter topologies and semiconductor devices with application of cold plate cooling and LCL filter. Design for high power inverter is evaluated with demonstration of 50 kVA 2 level 3phase SiC inverter operating at 60 kHz switching frequency. The prototype achieves high gravimetric power density of 6.49 kW/kg.
EXISTING SYSTEM:
Increase of electric loads in the MEE (to replace mechanical loads) results in more number of power inverters to interface them. Thus, power converter with emphasis on weight and volume minimization becomes crucial. While some works on HPDC had been reported in the literature review, most of them emphasized on volume minimization or in lower power rating range inverter. This paper presents design methodology for HPDC by considering different topologies and power devices selection, thermal management, and passive components to yield optimal switching frequency (f s ) for highest power per weight. This evaluation is establishing techniques to deliver high gravimetric power density power electronics benchmarked against the available technology. The application of commercial high power SiC devices is investigated and compared analytically to Si devices. To verify the proposed esign methodology, a design for a 50 kVA 3-phase 3-wire power inverter is evaluated and discussed as a sample case. To review the result of design methodology, a selected configuration of power converter is prototyped.
PROPOSED SYSTEM:
In order to achieve inverter design with maximum power density, various components that contribute to the total weight and volume of the inverter have to be considered. They mainly are the power module, DC-link capacitor, AC filter components, cooling system (e.g. heatsink), and miscellaneous parts such as control and protection board, casing, bus bar, etc. Finding optimal f s might not be straight forward as some of them are in trade-off relationship. While higher f s can result in lower capacitance and inductance requirement (in DC-link and AC filter), it results in higher switching loss in the power devices and consequently bigger cooling system requirement. Furthermore, different inverter topologies and power devices technologies also result in different loss distribution and passive components requirements. Therefore, we develop a design flow as shown in Fig. 2 which starts with inverter electrical and thermal specifications (power rating, frequency, ripple amount, coolant type and flow-rate, etc.). Details of the design process with objective to find the optimal f s for maximum power per weight value are discussed in the following sections.
CONCLUSION
A design methodology for high power density 3-phase inverter that focuses on weight minimization has been developed and elaborated by taking into account inverter specifications and various practical constraints. Optimal design of 50 kVA inverter has been presented by considering different inverter topologies and semiconductor devices with cold plate cooling and LCL filter application. Finally, a prototype of 50 kVA 2 level 3-phase SiC inverter operated at 60 kHz switching frequency is demonstrated. Measurement results verify the effectiveness of the designed LCL filter and the inverter’s efficiency of 97.7%. The 50 kVA prototype has power density of 6.49 kW/kg.
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