Control Design for 400 Hz Ground Power Unit

In this paper, a design of Sinusoidal Pulse Width Modulation (SPWM) 400 Hz inverter is proposed for Ground Power Unit (GPU) in airlines industry. In which, the inductor filter is integrated into the isolated transformer, for reducing the production volume, also enhancing the system flexibility and reliability. In the control scheme, resonant controller with parallel structure is performed to control fundamental harmonic voltages. The computation delay always existed in digital systems is considered to handle through the phase compensator technique. Simulation studies in Matlab software and Hardware in the Loop (HIL) show that the controller can regulate the output voltage, with the Total Harmonic Distortion (THD) is just 1.21% and 2.31%, respectively, even under the nonlinear load condition. The 20 kVA GPU experimental prototype using digital signal processing (DSP) has been implemented verify the validity and feasibility of the proposed controller. The control strategy steady state and the dynamic performance are tested in carefully, which show that the steady state error is relatively small, the transient response is fast and THD is 2.24% for the rectifier load.