Robust Sliding Mode Control of a Unipolar Power Inverter

Muhammad Awais,Abdul Rehman Yasin,Amina Yasin,Mudassar Riaz,Saba Zia,Bilal Saqib

doi:10.3390/en14175405

Abstract

The key issue in the practical implementation of the sliding mode (SM) control–based power inverter is the variable switching frequency. This variable switching frequency not only induces electromagnetic interference (EMI) noise, but also reduces the efficiency of the inverter, as the size of the inductor and capacitor does not alter in tandem with this variable frequency. In this context, fixed switching frequency–based SM control techniques are proposed; however, some of them are too complex, while others compromise the inherent properties of SM control. In this research, a fixed frequency SM controller is proposed, which is based on the novel low-pass filter extraction of the discontinuous control signal. This allows the technique to be implemented with fewer hardware components, thus reducing the complications of implementation, while maintaining the robustness and parametric invariance of SM control. A simulation-based comparison with an existing pulse width modulated (PWM) SM controller is presented as the benchmark. In comparison with the sigmoid function SM controller, an improvement of 50% in the settling time along with zero steady-state errors and a further 37% and 42% improvement in the undershoot and overshoot, respectively, is reported in the simulation. A hardware setup is established to validate the proposed technique, which substantiates the simulation results and its disturbance rejection properties.

Highlights

Single-phase pulse width modulation (PWM)–based unipolar inverters are an integral component for the realization of such systems
The unipolar PWM technique is selected for the inverter, due to its better performance in terms of total harmonic distortion (THD) and efficiency [35]
We propose a first-order RC filter with time constant τ = R1 C1, where R1 is the resistance and C1 is the capacitance of the filter

Summary

Introduction

Energy requirements have increased exponentially, and the increased use of conventional energy sources has had a detrimental effect on the environment. This has shifted the research focus toward renewable energy resources. Since solar energy is most abundant in nature, among other renewable energy resources, photovoltaic generation systems have emerged. Single-phase pulse width modulation (PWM)–based unipolar inverters are an integral component for the realization of such systems. The nonlinear loads affect the sinusoidal output voltage of inverters, as they increase the total harmonic distortion (THD), resulting in the difficulty of meeting IEEE standard 1547 [1,2,3,4]

Methods

Results

Conclusion