## 3 Simulation Results
### Storage-Supported Mode  
Figure 10 shows the dynamic power profiles of the fundamental, 5 th harmonic, 7 th harmonic, house-load inverter (HLI), and battery power over time under the storage-supported mode. The battery starts discharging (magenta line rises to around +300 W) at the beginning (t = 0.8 s) to help supply the load while the fundamental (cyan) and harmonic components (orange for 5 th and blue for 7 th) initially remain low. The HLI power (green line) remains nearly constant around 650 W, indicating stable delivery to the single-phase load.  
Figure 9: Inverter load voltage and current during load increase. (red: phase a, green: phase b, blue: phase c, purple: phase a, olive green: phase b, cyan: phase c).  
Between t = 1.6 s and 1.7 s, the system undergoes a mode transition: the battery switches to charging mode (the magenta line drops to around \(-\)500 W), and the power contribution from the grid (fundamental and harmonic components) increases sharply to take over the full load and supply additional power to charge the battery. This dynamic demonstrates how the harmonic-based power transfer adjusts to maintain system balance without affecting the load. The HLI power remains unaffected throughout the transitions, confirming that the DC-link isolation and inverter regulation maintain pure sinusoidal power at the load end. The system effectively demonstrates flexible energy sharing between the harmonics, the fundamental component, and the battery unit.  
The DC-link voltage stays close to constant at 400 V throughout the simulation period, including load transients, according to Figure 11.  
Figure 11: DC-Link voltage stability during power transfer and load variations.  
Figure 10: Dynamic power response of fundamental, harmonic components, HLI, and battery in storage-supported mode.  
Figure 12 shows the voltage and current waveforms at the single-phase HLI output. The top subplot shows the HLI voltage, while the bottom subplot shows the corresponding load current. Both signals are perfectly sinusoidal at 50 Hz, which means that the inverter is delivering clean fundamental frequency power to the load. The absence of visible harmonic distortion confirms that the DC-link and inverter stages are effective in isolating the load from any grid-side harmonic components, thus ensuring high power quality.  
Figure 13 shows the grid voltage and current waveforms when the 5 th and 7 th harmonics are injected during battery charge and discharge transitions. The upper plot shows the three-phase grid voltages, which are visibly distorted due to the injected harmonics, combining the 50 Hz fundamental with the 5 th and 7 th harmonics. The lower plot shows the corresponding grid currents, which also reflect harmonic content and dynamic behavior associated with the transition between charging and discharging modes. These current waveforms demonstrate the system's ability to manage harmonic-rich conditions while adjusting power exchange with the battery.  
Figure 12: Single-phase HLI load voltage and current showing clean 50 Hz waveforms.  
Figures 10-13 show that the storage-integrated mode is able to support the DC-link during load transitions and maintain stable voltage and a clean 50 Hz supply to the HLI. The system effectively isolates the load from the injected 5 th and 7 th harmonics on the grid side and demonstrates robust harmonic decoupling and energy support from the battery.