Abstract:

This paper presents a deadbeat-based proportional-integral (PI) controller for a stand-alone single-phase voltage source inverter using a battery cell as the primary energy source. The inverter system is simulated in MATLAB/Simulink. It consists of a lead acid battery, third-order Butterworth low-pass DC filter and AC filter, H-bridge inverter, step-up transformer, and a variety of loads, as well as its sinusoidal pulse-width modulation (SPWM) deadbeat-based PI controller. In this paper, 2 simulation case studies are carried out, which are the abrupt load changes from a 400 W resistive load to a 500 W resistive load, and from a 400 W resistive load to an inductive load of 500 W 0.85 power factor lagging. From the simulation results for both cases, the state-of-charge of the battery decreases due to supplying power to the loads, yet the battery voltage remains constant at about 36 V and the battery current exhibits a smooth ripple despite the current spikes produced by the H-bridge inverter, which will prolong the lifespan of the battery. This shows that the DC filter performs satisfactorily to isolate the current spikes generated by the SPWM controller and H-bridge inverter. Moreover, even though the load varies for both cases, the sinusoidal inverter output voltage can be tracked and maintained at 230 Vrms with a 50 Hz frequency within a few cycles from the instant that the load is changed, as well as a low total harmonic distortion voltage (THDv) content of 1.53% and 2.78%, respectively. This indicates that the controller proves its robustness and stiffness characteristics in maintaining the output load voltage at the desired value to supply the power for a variety of loads with a minimum THDv.

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