Microsoft Word - ver 4 assignment_2.docx ELEC9711 – Power Electronics for Renewable and Distributed Generation Systems Assignment 2 For the single-phase bi-directional grid-connected voltage source...

For the single-phase bi-directional grid-connected voltage source converter shown in Fig. 1

1. 
   

   (a) draw a simplified block diagram of the single-phase d-q current controller to control the
   

   
   

   d-q component of the injected grid current.
   

   
   


2. 
   

   (b) draw a simplified block diagram of the controller when the converter is operating as a
   

   
   

rectifier. Provide explanations for the control block diagram.

Microsoft Word - ver 4 assignment_2.docx ELEC9711 – Power Electronics for Renewable and Distributed Generation Systems Assignment 2 For the single-phase bi-directional grid-connected voltage source converter shown in Fig. 1 (a) draw a simplified block diagram of the single-phase d-q current controller to control the d-q component of the injected grid current. (b) draw a simplified block diagram of the controller when the converter is operating as a rectifier. Provide explanations for the control block diagram. Grid Cdc Vdc dc Voltage Bus isa LsR vsa S4S2 S1 S3 PCC o Fig. 1. Single-phase Grid-connected Converter The following data is provided:  Grid-voltage 240V (rms), 50-Hz AC supply at the point of common coupling (PCC).  AC source/filter inductance Ls = 5 mH, and leakage resistance R of the filter = 0 Ω.  Switching-frequency of the converter = 5 kHz (Assume IGBT as switching devices).  Input DC-voltage is maintained constant to 380V. For the two conditions given below, i. The converter draws 20 kW of power in rectifier mode at unity power-factor. ii. The converter supplies 15 kW of power to the grid with 0.866 power factor. (c) compute the d-q component of the grid voltage. Also, compute the d-q reference values for the converter input current. (d) Develop a simulation model and verify that your model results agree with your numerical calculations.