7. PLECS PIL Based Case Studies

In the previous three chapters extensive use has been made of VisSim embedded control software to realize sensorless control of three-phase AC machines using the InstaSPIN approach. In all cases a hardware set up as shown in Fig. 7.1 (top part) was used to access the LAUNCHXL-F28069M, whereby a PWM/ADC module was provided for data acquisition/control of the converter via a gate driver. In this chapter the PLECS based ‘processor in the loop’ approach is considered, as shown in Fig. 7.1 (bottom part). This PIL module can replace the ADC input variables (and additional inputs if needed) by those generated by an ‘ADC model’, which in turn is connected to an electrical model of the drive. In addition, the PWM output signals which are normally used to drive the hardware converter are now redirected to a ‘PWM model’ that generates the gate signals for the model converter. A high speed data link ensures that the code running on the actual MCU is tied to the PLECS simulation model. Furthermore, the execution of the simulation and embedded code is fully synchronized. In contrast to earlier chapters the Texas Instruments development environment ‘Code Composer’ is used here, which has access to a series of InstaSPIN MotorWare development laboratories [9]. Specifically two MotorWare development laboratories will be considered in this chapter, given that these are ‘PIL’ prepared, which implies that the necessary additional PLECS code has been added to enable use of the PIL approach discussed in this chapter. A processor board with a F28069M device must be connected via USB, to enable PLECS PIL operation. The key differences with the VisSim PIL approach discussed previously is the use of a switching converter that may contain ideal or non-ideal devices. With the aid of the approach set out in this chapter a user can fully develop a PLECS PIL based software environment that can be tested with a simulated drive, prior to use with the actual hardware. Note however, that this type of development requires a certain amount of C-code literacy.