The closed-loop control of a three-phase inverter using a DSPACE DS1102 DSP board

Abstract

Due to enhanced reliability, reductions in cost, and ease of maintenance, the U.S. Navy has decided to shift from radial electrical distribution to DC zonal distribution for shipboard use. Correspondingly, the construction of newer classes of combatant vessels will replace bulky transformers with semiconductor switching DC-DC converters and DC-AC inverters. Electrical Control Units, ECUs, control these converters and inverters. Development of an ECU begins with a prototype design, used by the engineer to test the ability of an experimental algorithm to control a physical system. This thesis research examines the use of the DSPACE DS1102 DSP board as a prototype ECU for a three-phase inverter. A DS1102 monitored currents at the output of a three-phase power MOSFET bridge, performed the signal processing, and accordingly provided the MOSFET gating signals. This research compared several different algorithms, time steps and integration methods implemented by the DSP board. In the experiments, the inverter powered a simple RL load and an induction motor. For the closed-loop control of the induction motor, a speed control algorithm provided command inputs to the previously tested inverter. This thesis research demonstrates that the DS1102 can quickly and effectively prototype the signal processing and control units of the electrical power distribution systems of future U.S. Navy ships.