A power conversion system, comprising: a rectifier operative to convert AC input power from a three-phase power source to provide DC power to a DC bus; an inverter operative to generate at least one AC output signal to drive a load using power from the DC bus; and a detection system comprising: a filter operative to provide a filter output signal or value representing an amplitude of a predetermined harmonic of a fundamental frequency of the AC input power in a voltage (Vdc) of the DC bus, and a logic circuit operative to detect at least one of excessive ripple on the DC bus and phase loss associated with the AC input power based at least partially on the filter output signal or value, wherein the filter comprises: a first bandpass filter operative to provide a first filter output signal or value (v 2 _amp) representing an amplitude of a second harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus, and a second bandpass filter operative to provide a second filter output signal or value (v 6 _amp) representing an amplitude of a sixth harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus; and wherein the logic circuit is operative to: detect excessive ripple on the DC bus if the second filter output signal or value (v 6 _amp) exceeds a predetermined ripple threshold (TH R), and to detect phase loss associated with the AC input power if a ratio of the first filter output signal or value (v 2 _amp) to the second filter output signal or value (v 6 _amp) exceeds a first predetermined threshold (TH PL1). a rectifier operative to convert AC input power from a three-phase power source to provide DC power to a DC bus; an inverter operative to generate at least one AC output signal to drive a load using power from the DC bus; and a detection system comprising: a filter operative to provide a filter output signal or value representing an amplitude of a predetermined harmonic of a fundamental frequency of the AC input power in a voltage (Vdc) of the DC bus, and a logic circuit operative to detect at least one of excessive ripple on the DC bus and phase loss associated with the AC input power based at least partially on the filter output signal or value, wherein the filter comprises: a first bandpass filter operative to provide a first filter output signal or value (v 2 _amp) representing an amplitude of a second harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus, and a second bandpass filter operative to provide a second filter output signal or value (v 6 _amp) representing an amplitude of a sixth harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus; and wherein the logic circuit is operative to: detect excessive ripple on the DC bus if the second filter output signal or value (v 6 _amp) exceeds a predetermined ripple threshold (TH R), and to detect phase loss associated with the AC input power if a ratio of the first filter output signal or value (v 2 _amp) to the second filter output signal or value (v 6 _amp) exceeds a first predetermined threshold (TH PL1). a filter operative to provide a filter output signal or value representing an amplitude of a predetermined harmonic of a fundamental frequency of the AC input power in a voltage (Vdc) of the DC bus, and a logic circuit operative to detect at least one of excessive ripple on the DC bus and phase loss associated with the AC input power based at least partially on the filter output signal or value, wherein the filter comprises: a first bandpass filter operative to provide a first filter output signal or value (v 2 _amp) representing an amplitude of a second harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus, and a second bandpass filter operative to provide a second filter output signal or value (v 6 _amp) representing an amplitude of a sixth harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus; and a first bandpass filter operative to provide a first filter output signal or value (v 2 _amp) representing an amplitude of a second harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus, and a second bandpass filter operative to provide a second filter output signal or value (v 6 _amp) representing an amplitude of a sixth harmonic of the fundamental frequency of the AC input power in the voltage (Vdc) of the DC bus; and wherein the logic circuit is operative to: detect excessive ripple on the DC bus if the second filter output signal or value (v 6 _amp) exceeds a predetermined ripple threshold (TH R), and to detect phase loss associated with the AC input power if a ratio of the first filter output signal or value (v 2 _amp) to the second filter output signal or value (v 6 _amp) exceeds a first predetermined threshold (TH PL1).