<p>Thus far, the realization of large rotation angles at reasonable voltages has proven elusive in parallel-plate electrostatic MEMS scanning mirrors. In this study, we present a mirror that can achieve large rotation angles with a resonant voltage amplitude less than 30V. The mirror features in-plane side electrodes. Electrostatic forcing drives the first surge mode of the mirror at its primary resonance. Commensurate ratios of 2:1 and 3:1 between that mode and the first pitch mode channel energy to the latter through auto-parametric resonance. Absent the need for a bottom electrode, back etching of the substrate allows the mirror plate to realize large angles driven by this energy channel. We demonstrate the formation of those energy channels experimentally in the case of 3:1 surge-pitch modal interaction, and numerically for both 2:1 and 3:1 surge-pitch modal interactions. Our experimental findings indicate the presence of mechanical and electrostatic coupling terms between the two modes creating the 3:1 energy channel. We also found experimentally and numerically that quasiperiodic orbits develop in a limited frequency range within the modal interaction regime. Those orbits can create soliton frequency combs and their concomitant wavepackets.</p>