AC Cube — Single-Stage PV/Battery/Grid Energy Router
A single-stage isolated converter that unifies PV, battery and grid into one conversion stage instead of the usual stack of separate converters. Built on the inertia-less isolated converter, the prototype delivers 240 Vac from a 48 Vdc source using a \(\Sigma\)–\(\Delta\) modulation scheme.
Why single-stage
A conventional PV-plus-storage installation chains several converters together, each with its own DC link, its own capacitor bank and its own losses. Collapsing that into one isolated stage removes the intermediate storage element — the “inertia” — and with it the component that most often ends the system’s life.
Approach
- Bidirectional single-stage isolated topology with an ultra-low-leakage transformer.
- Pulse density modulation (\(\Sigma\)–\(\Delta\)) for AC synthesis.
- Zero-voltage and zero-current switching across the operating range.
- AC-side switching, with PV, battery pack and grid all routed through the one stage.
Prototype
| Parameter | Value |
|---|---|
| Power | 1 kW |
| Input | 48 Vdc |
| Output | 240 Vac |
| Modulation | \(\Sigma\)–\(\Delta\) / pulse density |
Citation
S. Manjrekar, A. Marellapudi, S. Belkhode, J. Benzaquen and D. Divan, “‘AC Cube’: A Single-Stage PV/Battery/Grid Energy Router,” 2025 IEEE Energy Conversion Congress & Exposition Asia (ECCE-Asia), Bengaluru, India, 2025, pp. 1–6.