Power converter
The present invention relates to power converters of the type known generally as switch mode power converters (SMPCs). In particular, the present invention addresses the problem of reducing thermal stress across the phases of a multi phase converter. Specifically, a method of controlling a multi-phase switch mode power arrangement is provided. The multi-phase arrangement comprises a plurality of phases configured to deliver DC power to a common load. The method comprises the steps of: determining the thermal stress of each phase along with at least one other stress for each phase and controlling the share of DC power provided by the individual phases in an effort to equalize the thermal and other stress across the individual phases.
1. A method of controlling a multi-phase switch mode power arrangement comprising a plurality of phases configured to deliver DC power to a common load, the method comprising:
determining the thermal stress of each phase;
determining at least one other stress of each phase; and
controlling the share of DC power provided by the individual phases in an effort to equalize the thermal stress and at least one other stress across the individual phases,
wherein the thermal stress of one phase is dynamically elected as a master thermal stress, and the duty cycles of the individual phases are adjusted by a weighted amount determined by differences between their individual thermal stress and that of the master thermal stress and wherein the at least one other stress of one phase is dynamically elected as the master at least one other stress, and the duty cycles of the individual phases are adjusted by a weighted amount determined by differences between their individual at least one other stress and that of the master at least one other stress.
2. A method of controlling a multi-phase switch mode power arrangement in accordance with claim 1 , wherein the at least one other stress comprises a current stress.
3. A method of controlling a multi-phase switch mode power arrangement in accordance with claim 1 , wherein the at least one other stress comprises a voltage stress.
4. A method of controlling a multi-phase switch mode power arrangement in accordance with claim 1 , wherein the share of DC power provided by the individual phase is determined by a weighted function.
5. A method according to claim 1 , wherein the thermal stress of each phase is determined by a co-located temperature sensor.
6. A method according to claim 5 , wherein the co-located temperature sensors are positioned to measure the temperature of the switching elements of the phases.
7. A method according to claim 1 , wherein a controller controls the share of DC power provided by the individual phases by performing closed-loop control of the phase duty cycles of the individual phases.
8. A switch mode power arrangement for delivering DC power to a load, the arrangement having a plurality of phases sharing the supply of power to the load, wherein the arrangement is configured in response to the determined thermal stress and at least one other stress of each individual phase to adjust the share of power provided by the individual phases in an effort to equalize the thermal stress and at least one other stress across the plurality of phases, and a controller configured to dynamically elect a stress signal from sensed signals of a common type of stress received from the plurality of phases as a master stress signal of that type.
9. A switch mode power arrangement as claimed in claim 8 , wherein each phase comprises a controller and a temperature sensor linked with the controller.
10. A switch mode power arrangement as claimed in claim 8 , wherein the arrangement is configured to perform closed-loop control of the phase duty cycles.
11. A device, comprising:
a modulator for switching at least one switching device in a phase of a switch mode multi-phase power arrangement for delivering DC power to a load, wherein the modulator is adapted to receive a communicated duty cycle signal, a communicated thermal stress signal and at least one other communicated stress signal, and wherein the modulator is adapted to adjust the received duty cycle in and to provide the adjusted duty cycle to the at least one switching device, wherein the modulator is further adapted to adjust the duty cycle in response to a combination of:
a) a difference between the received thermal stress signal and a sensed thermal stress signal of the phase, and
b) a difference between the received other stress signal and a sensed other stress signal of the phase.
12. A device according to claim 11 , wherein the combination is a weighted combination.
13. A device according to claim 11 , further comprising:
at least one switching device, a temperature sensor for sensing temperature in the device to provide a sensed temperature and a sensor for sensing the other stress signal.
14. A device according to claim 13 , wherein the device is configured to communicate the sensed temperature and sensed other stress signal to a central controller.