A simplified implementation of NLSPWM control strategy for SqZS inverter via model-driven processor programming method

The transformerless single-phase semi-quasi-Z-source inverter (SqZSI) has a nonlinear gain curve and requires nonlinear sinusoidal pulse width modulation (NLSPWM) to achieve sinusoidal voltage at the output AC terminal. Although the SqZSI provides some advantages, for example, leakage current elimination, doubly grounded, low volume, and low cost, it needs nonlinear modulation control. The NLSPWM is relatively complex among single-phase modulation methods and it is considered a disadvantage for this topology, so this paper presents a model-driven processor programming method that facilitates the implementation of NLSPWM. The developed programming method utilizes a Blockset environment in MATLAB/Simulink to implement NLSPWM, and then the obtained model is compiled and directly uploaded to the ARM Cortex-M4-based STM32F4 processor. In this approach, there is no need for coding in C programming language, and only the Simulink mathematical blocks are used so it simplifies the implementation process. The same Simulink model used to model the inverter control is slightly edited for implementation, which accelerates the debugging cycle. Experimental results of 100 W SqZSI confirm the desired and accurate performance of this low-cost method. The qualitative comparison of the processor programming methods and the performance comparison of the developed SqZSI based on this approach verify the simplicity of implementation.