ZYNQ-7000 High Performance Electric Drive and Silicon Carbide Multilevel inverter with SCILAB Hardware-in-the-loop – ScilabTEC 2015

By Giulio Corradi, Xilinx & Diego Quagreda, QDESYS

ScilabTEC 2015 - Xilinx from Scilab on Vimeo.

QDESYS and Xilinx have developed a High Performance Electric Drive capable of being controlled in real-time using SCILAB and Xilinx ZYNQ-7000®. This system allows standard Drives as well as Multilevel Inverter with Silicon Carbide as state of the art design platform. Power electronics control designers often use simulation to design their systems and they validate it on the target platform. Such models contain simplification that may affect the viability of the derived controller. More and more control systems are used in distributed environment and data communication and also time delays may affect the simplified model in such way that it responds poorly when deployed in the real system. Such poor response requires adjustments in the simulation environment, new assumptions and new testing on the target system making the development of power electronic a long iterative process.

Recent programming environments and faster processors have greatly reduced the iterative process effort providing ways to compute more accurate models; however the problem and uncertainty is still forcing the designers to simulate-test-change-model loop that is tedious and not really always practicable. A more natural way can be using the real system imbedded with the simulation environment making the iterations less cumbersome.

With traditional processing systems the hardware in the loop approach while desirable is difficult to achieve, and almost not applicable on microcontrollers, due to their limited amount of processing power. To make things even more difficult in power electronic systems the evolution of events, variables, and commands spans several orders of magnitude; from the hundreds of nanoseconds of position sensor like a rotary encoder that measures the shaft’s angle, to the microseconds of the analog to digital converter that measures the feedback currents up to the millisecond range of motor’s rotation.

Serial processors have hard time to match such timing requirements without imposing a tight scheduling ordering on the control and acquisition process. Power engineers and the control engineers are always struggling in assuring that such scheduling is not violated and possible modifications or even product adaptations is not affecting the overall performances.

Because of the high parallelism involved in high performance motor control a parallel system that can exploit efficiently the timing differences between the events, sensors and motor is definitely more desirable. A DLL for Scilab has been designed to connect to ZYNQ-7000® via UDP/IP allowing 1Gigabit communication to the Drive.

References
[1] https://www.youtube.com/watch?v=8ZS0zDGPCwc