Fault tolerant motor drives for powered wheelchairs

Abstract

A motor drive circuit consisting of the bridge and the interface unit is described. The behavior of current flow in the nonredundant bridge is shown. Failure modes in this bridge are described. In order to provide fault tolerance, a number of new designs using passive and active redundancy are presented and analyzed. An analysis of these designs is done. An interface unit for driving the high-side nFET is developed using the principles of bootstrapping. Calculations of the capacitance and resistance in this circuit are described. Finally, some test results using SPICE and some experimental results on the circuit implemented are presented.<>