Reliable current sensing for inverter-controlled electric machine

An electric drive for an electric vehicle with a multi-phase electric machine, comprising:

• an inverter bridge having inverter switches arranged in a plurality of phase legs;
• an inverter controller for controllably switching the inverter switches;
• first and second phase conductors coupled between respective inverter phase legs and respective phase windings of the electric machine;
• first and second flux cores each having a central passage and a gap, respectively, wherein the first and second phase conductors pass through the central passages of the first and second flux cores, respectively;
• a first plurality of current sensors comprised of a predetermined number of first Hall-effect devices, each of the first Hall-effect devices disposed in the gap of the first flux core to generate respective first current signals;
• a second plurality of current sensors comprised of the predetermined number of second Hall-effect devices, each of the second Hall-effect devices disposed in the gap of the second flux core to generate respective second current signals;
• and
• a plurality of multi-channel op amp devices for conditioning the current signals and coupling them to an inverter controller, wherein the number of multi-channel op amp devices equals the predetermined number;
• wherein each one of the first Hall-effect devices is connected to a different one of the op amp devices, and wherein each one of the second Hall-effect devices is connected to a different one of the op amp devices, whereby a valid conditioned current signal corresponding to each phase conductor is received by the inverter controller unless there are multiple failures of the Hall-effect devices and the op amp devices.