Three-Phase Motor Inverter and Current Sensing GaN Power IC

Abstract

A three-phase GaN-based motor inverter IC with three integrated phase current mirror sensors (sense-FETs or sense-HEMTs, 1200:1 ratio), a temperature sensor, and an amplifier is presented and experimentally operated. The three low-side currents are read out by virtual grounding transimpedance amplifiers. A modified summed DC current readout circuit using only one amplifier is also discussed. During continuous 24 V motor operation with space-vector pulse width modulation (SVPWM), the sensor signal is measured and a bidirectional measurement capability is verified. The measured risetime of the sensor signal is 51 ns, indicating around 7 MHz bandwidth (without intentional optimization for high bandwidth). The IC is operated up to 32 V on DC-biased semi-floating substrate to limit negative static back-gating of the high-side transistors to around −7% of the DC-link voltage. Analysis of the capacitive coupling from the three switch-nodes to the substrate is calculated for SVPWM based on capacitance measurement, resulting in four discrete semi-floating substrate voltage levels, which is experimentally verified. Integrated advanced power converter topologies with sensors improve the power density of power electronics applications, such as for low-voltage motor drive.

Improved Feedback Quantizer with Discrete Space Vector

“…Thanks to technological advances, researchers have created various converter topologies and control schemes to meet the needs of each application [ 1 , 2 , 3 , 4 , 5 ]. These applications include AC motor drives [ 6 ], renewable energies [ 7 ], HVDC systems [ 8 ], electromobility [ 9 ], and microgrids [ 10 ].…”