Design of Three-Phase, 400Hz Power Supply using Three-Level T-Type Topology and It’s Reliability Analysis

Abstract

Aircraft electrical equipments operate on many different voltages such as AC and DC. However, most of the aircraft systems uses 115 V (AC) at 400 Hz or 28 V DC supply. As aircraft fly higher and faster, small size and less weight of electrical apparatus is the major matter in it’s design. The only way to meet this power requirement is to increase the frequency of the supply. A high frequency power supply allows more power to be access for the same size and weight of the motor. So, there is always tread-off between size and efficiency of the power supply. In the proposed work 400 Hz is taken as optimum switching frequency. In this project three phase, 400 Hz power supply is generated using three level T-type topology. To generate this power supply, T-type inverter is controlled by space vector pulse width modulation (SVPWM) technique and three phase modulating signals Rpwm, Ypwm and Bpwm are generated by using phase disposition PWM (PDPWM) technique to control the switching devices (IGBTs). This project also presents a design of output passive filter with it’s damping components to reduced the harmonics from the output of the given system. The performance of T-type multilevel inverter is simulated and studied under no-load condition and with three phase R-Load which is of 110 kW in PSIM software. Various performance parameters like output voltage, output current, it’s %THD calculation etc, are discussed. Hardware prototype of this simulated system is also implemented. This hardware design employs a high-performance TMS320F28375 digital signal processor (DSP) from texas instruments. At last the simulated results are verified with experimental results. The reliability of power electronic apparatus and components is very important for the manufacturers. The reliability of 400 Hz power system is analysed by calculating the mean time between failure (MTBF) for each of the component present in the system. For this reliability analysis MILHDBK-217F database is used. And from this particular database part stress method is used to calculate the MTBF of the control card. Other sources of data are taken from component manufacturers or data-sheets of each component.