A drive system comprising: a machine including a plurality of phases and configured to generate power based on a plurality of phase currents, each respectively associated with the plurality of phases; a direct current bus, operatively connected to the machine, the DC bus including a high-side line, a low-side line, and an inverter including a plurality of switching systems (31a, 31b, 31c), operatively connected between the high-side line and the low-side line, the plurality of switching systems (31a, 31b, 31c) each configured to output a respective one of the plurality of phase currents, wherein at least one of the plurality of switching systems (31a, 31b, 31c) includes a high-side switching system operatively connected to the high-side line, the high-side switching system configured to output the phase current associated with the at least one of the plurality of switching systems (31a, 31b, 31c), and a low-side switching system operatively connected to the low-side line; a controller operatively connected to the DC bus and the machine, the controller configured to determine if a failure exists in the drive system based on the plurality of phase currents and a DC bus voltage, the DC bus voltage being a voltage across the high-side line and the low-side line, and a plurality of current sensors configured to respectively measure the plurality of phase currents and to output measurement signals including the measured phase currents, the controller being configured to receive the measurement signals, wherein the controller is configured to determine an over current value for the high-side switching system, characterized in that the controller is configured to activate the high-side switching system and to determine if an over current failure exists based on the measured phase current and the over current value. a machine including a plurality of phases and configured to generate power based on a plurality of phase currents, each respectively associated with the plurality of phases; a direct current bus, operatively connected to the machine, the DC bus including a high-side line, a low-side line, and an inverter including a plurality of switching systems (31a, 31b, 31c), operatively connected between the high-side line and the low-side line, the plurality of switching systems (31a, 31b, 31c) each configured to output a respective one of the plurality of phase currents, wherein at least one of the plurality of switching systems (31a, 31b, 31c) includes a high-side switching system operatively connected to the high-side line, the high-side switching system configured to output the phase current associated with the at least one of the plurality of switching systems (31a, 31b, 31c), and a low-side switching system operatively connected to the low-side line; a controller operatively connected to the DC bus and the machine, the controller configured to determine if a failure exists in the drive system based on the plurality of phase currents and a DC bus voltage, the DC bus voltage being a voltage across the high-side line and the low-side line, and a plurality of current sensors configured to respectively measure the plurality of phase currents and to output measurement signals including the measured phase currents, the controller being configured to receive the measurement signals, wherein the controller is configured to determine an over current value for the high-side switching system, characterized in that the controller is configured to activate the high-side switching system and to determine if an over current failure exists based on the measured phase current and the over current value.