Real time emulation environment for digital control development

Abstract

Simulation is a powerful tool for developing electric drive systems. Simulations allow the designer to experiment with control algorithms and hardware systems in a safe environment. To this end simulation is becoming increasingly popular. On'-line simulation does have its limitations in that the controller developed during the simulation period has eventually to be transferred to the target processor which will operate in the actual drive system. If, however, a real-time simulation environment could be realised, then the actual controller running in the actual target processor could be included in the simulation. Therefore no translation of code would be required once the controller had been developed and tested within the simulation. This would obviously lead to a reduction in development time and eliminate any possibility of introducing errors due to the translation between the simulated and actual controllers. This thesis describes the development of such a system using a multiple digital signal processing environment. The real-time simulated drive is operated in parallel with an experimental drive to allow a direct comparison between the two. The ability of the multiple processing system to operate in real-time has allowed the whole concept of simulation to be taken a stage further by the development of a real-time power level simulator. This simulator is capable of emulating a machine and load in real-time with real level of voltage and current. It is designed to replace a real machine during the development and testing stages of drive manufacture. This Virtual Machine is a controllable source/sink which is driven by the real-time simulation, and because of this the Virtual Machine takes on the characteristics of any choice of model within the real-time simulation. Moreover, because of its ability to handle bi-directional power flow, the Virtual machine can be programmed to emulate motors or generators. The Virtual Machine also includes the emulation of loads, thus making it extremely flexible and of interest to applications such as machine tools, electric vehicles, and wind generators, to name but a few.