Research About the Positive and Negative-sequence Detection Phase-locked Loop

Jingjing Li, Renjie Zhang, Jian Zhao
2017 DEStech Transactions on Engineering and Technology Research  
Under the condition of three-phase unbalance voltages, the software phase-locked loop(SPLL) outputs an error angle which contains harmonic component due to the negative-sequence component. This paper proposes a method to remove the phase effect by eliminating negative-sequence component. This method makes a positive and negative-sequence detection for the three-phase voltage with the way of decoupling through closed loop feedback. The method is verified by an experiment which established the
more » ... model with Matlab. The Experiment result shows that the SPLL has a good performance in dynamic response and stability. With the extensive use of distributed electric power generation system, the electric generator which has great power provides massive energy supply, so reliability is very important for the electric generator. Grid disturbance generator used to assess distributed electric power generation system will undergo the change from low power to high power. Typically, Grid disturbance generator with high power expands the capacity by parallel mode. For every parallel unit, it must be qualified with the ability to lock and trace the phase and frequency of fundamental wave rapidly in order to keep synchronization with the electric network. PLL can get the phase angle of grid voltage. The basic function of PLL is to obtain the phase of positive-sequence component of three-phase voltages. If necessary, frequency and amplitude can also be acquired by PLL. All of above signals PLL got play a role in the control of power transformer, so the performance of PLL will directly affect the outputs of the power transformer.
doi:10.12783/dtetr/mimece2016/10003 fatcat:nto5qgfmb5ek7gnfg54h4mclca