Patent ID: 8917066

Claim:
A method of controlling shunt utilization in a power converter sharing a DC bus with at least one other power converter, wherein the DC bus includes a first rail and a second rail, the method comprising the steps of: monitoring a magnitude of a voltage present on the DC bus; connecting a shunt device between the first rail and the second rail to discharge a desired amount of power when the magnitude of the voltage present on the DC bus exceeds a threshold, wherein the shunt device is connected in a modulated manner such that the shunt device is connected between the first rail and the second rail for a first portion of a periodic interval and disconnected for a second portion of the periodic interval and wherein the ratio of the first portion to the second portion defines a duty cycle of the modulation; determining a utilization rate of the shunt device, wherein the utilization rate is a function of a duration of time when the magnitude of the voltage present on the DC bus exceeds the threshold, increasing when the shunt device is being modulated between the first and the second rail and decreasing when the shunt device is not being modulated between the first and the second rail; and decreasing the desired amount of power discharged by the shunt device as the utilization rate increases.