Study On The Power Hardware-in-the-Loop Test System Of Two-Level Inverter

This thesis presents an alternative approach for Power Hardware-in-the-Loop(PHi L)testing of two-level inverter for drive applications.For this purpose the inverter is not connected to a real machine,but to a second power inverter instead,which acts like an electrical machine.The second inverter is called “Virtual Machine” and the testing system based on “Virtual Machine” is called Power Hardware-in-the-Loop test system.Generally,“Virtual Machine” is consisted of inverter,modulator,inverse machine model,and speed encoder simulator,which are introduced in chapter two and chapter three respectively.In chapter 2.1 the two-level inverter model and the calculation of main circuit parameters is introduced firstly;then,in chapter 2.2 the dynamic mathematical models of the squirrel-cage-rotor machine and permanent magnet synchronous machine are analysed;last,in chapter 2.3 the basic idea of SVPWM is depicted,the modulator with this method generates the pulses signal used for inverter.In chapter three the squirrel-cage-rotor inverse machine model and the permannet magnet inverse machine model are builded based on the space vector theory by signal flow graph method;the speed encoder simulator generates the traces A,B and Z depending on the angular velocity calculated by the inverse machine model;in addition,nine test methods for inverter are choiced.In chapter 4,the power hardware-in-the-loop test system is finished through MATLAB/Simulink software.For squirrel-cage-rotor virtual machine power hardware-in-the-loop simulation,the research method is divided into three steps:1.Build Field-oriented control simulation model of squirrel-cage-rotor machine;2.Build Field-oriented control simulation model of squirrel-cage-rotor machine with inverse machine model;3.Build Field-oriented control simulation model of squirrel-cage-rotor machine replaced by “Virtual Machine”.Permanent magnet virtual machine power hardware-in-the-loop research method is similar to squirrel-cage-rotor virtual machine.The simulation results show that the presented “virtual machine” has the same characteristics as a real machine.An inverter can be tested without a real machine.