A power system includes a power conversion stage that receives power from an input source and delivers power to a load via a power distribution bus. A control system samples the voltage delivered by the power conversion stage at a location close to the output of the power conversion stage and the load voltage at a location close to the load. The control system further measures the current flowing between the output and the load through the power bus. The samples may be used to determine a representation of the bus resistance. The determined bus resistance may be used to introduce a negative resistance characteristic in the power conversion stage as a way of compensating for the actual bus resistance.