An FPGA-Based On-the-Fly Reconfigurable Low-Power SHEPWM Inverter With a Compact SiP Implementation

This article presents a selective harmonic elimination pulsewidth modulation (PWM) (SHEPWM) full-bridge inverter featuring real-time on-the-fly reconfigurability of output waveform amplitude and frequency using a field-programmable gate array (FPGA). The inverter is integrated on a compact three-dimensional (3-D) system-in-package using low-temperature cofired ceramics as a substrate, reducing the printed circuit board (PCB) area. Validated through simulations and measurements at
$0.12 \,\mathrm{W}$
and
$1.2 \,\mathrm{W}$
peak output power, the inverter cancels harmonics up to the 34th order at switching nodes. With an
LC
filter having a
$20 \,\text{k}\text{Hz}$
cut-off frequency, total harmonic distortion at the load is below 5.1% for alternating current output signals, varying in modulation index from 0.2 to 0.9 and output frequencies from 5 to 10 kHz. The results also showed that for the same inverter conditions and output THD, the SHEPWM inverter with
$0.12 \,\mathrm{W}$
output power has an average of 17.3% and 4.2% better efficiency than a natural PWM (NPWM) inverter with an output frequency of
$4 \,\text{k}\text{Hz}$
and
$10 \,\text{k}\text{Hz}$
, respectively. For the inverter of
$1.2 \,\mathrm{W}$
output power, the SHEPWM inverter maintains better efficiency than the NPWM counterpart, by an average of 2.3% and 6.9%, respectively.