Research On Control Of High-power Permanent Magnet Motor Drive With Parallel Inverters

Permanent magnet synchronous motors(PMSM)are typically utilized in applications which require high-performance and high-efficiency motor drives.High power IGBT modules are needed to build high power motor drives for high power PMSM.However,such IGBT modules are cost expensive and its loss is high.In this thesis,parallel inverter solution is used to drive high power PMSMs.By using standard low power rating IGBTs,this solution has features of low cost,low power loss density and strong expansibility.This research is focused on Field Oriented Control(FOC)coupled with a master-slave control scheme to control a high-power PMSM with parallel inverters.The master controller generates the reference current from the measured motor speed.The slave controllers perform the FOC control and generate reference voltages to control the output current.The speed controller of the master controller and the current controllers of the slave controller are all PI controllers.The controller gains are determined based on the desired operation bandwidth of the speed and current control loops.The design and control of parallel inverter motor drive was done in two steps: firstly,the output filter is designed,and a single inverter drive with output filter is implemented.Later,the control of parallel inverter with output filter is implemented.Results from the simulations show that for a single inverter design,all the current stresses are handled by a single inverter,hence the loss density is high.This situation is eliminated by the introduction of the parallel inverter design.The proposed parallel inverter control method is validated by simulation.