Modelling and control of single VSI leading experimental hybrid power system integrating a wind turbine simulator
This paper discusses a hybrid wind diesel system aims to validate wind powered section of the experimental system. The experimental system proposed consists of a wind turbine simulator, a permanent magnets generator, a diode bridge rectifier, a step down converter, a bank of battery, a load and a control unit. An other operation of three-phase, four-wire voltage source inverter (VSI) under unbalanced voltage conditions is also investigated.
Research on control strategies for distributed inverters in low voltage micro-grids
Taking into account the configuration of low voltage distributed grids. The micro-grid that is consisted of three-phase four-leg inverters is proposed in this paper. Then, a decomposing sequence control strategy and a droop control method are explored. Positive, negative and zero sequence components can be controlled by the decomposing sequence control method independently. The decomposing sequence control algorithm is implemented in dq0 reference frame, which can achieves voltage regulation with low THD and fast transient response, and inverters can output a set of symmetric ac voltages under various loads. Meanwhile, inverter' output impedance is fixed through a virtual impedance scheme. The droop-control method is applied to regulate the frequency and amplitude of inverters output voltages, which only use local measurements of the inverter. These control strategies can improve the modularity, reliability and flexibility of the distributed power supplies. The total loads are shared among inverters by the propose control strategies. Simulation results are provided from two 6KVA parallel-connected inverters in an island micro-grid, which verifies the validity of method proposed.
Recovering the frontier state : war, ethnicity, and state in Afghanistan
Chapter 1 Table of Contents Chapter 2 1 Introduction Chapter 3 2 Ethnicity, Political Power, and Fragmentation Chapter 4 3 Rise of the Taliban and Civil War Chapter 5 4 The United States and War on Terrorism Chapter 6 5 Restructuring the Afghan State Chapter 7 6 Political Economy of Drugs and Warlordism Chapter 8 7 Afghanistan and Neighboring States Chapter 9 8 Conclusion Chapter 10 Bibliography