Modulation of switching signals in power converters

A power converter switching device control system, the switching device for coupling a direct current (DC) source to provide an alternating current (AC) output at a particular switching frequency, the power converter switching device control system comprising:

• a controller for switching the switching device in the power converter according to a modulation scheme, the controller being arranged to switch the switching device, in each of a plurality of switching periods, between active configurations providing a finite voltage at the AC output and inactive configurations providing a zero voltage at the AC output;
• wherein a ratio between a total period of time in which the switching device is in an active configuration and a total period of time in which the switching device is in an inactive configuration is the same for each of the plurality of switching periods and is determined according to a desired voltage at the AC output;
• and
• wherein, in each of the plurality of switching periods, there are at least two time periods in which the switching device is in the inactive configuration, and a ratio between those at least two time periods is changed in dependence on temperature associated with the switching device.

A switching power converter comprising:

• a switching device for coupling a direct current (DC) source to provide an alternating current (AC) output at a particular switching frequency;
• and
• a controller for controlling the power converter by switching the switching device according to a modulation scheme, the controller being arranged to switch the switching device, in each of a plurality of switching periods, between active configurations providing a finite voltage at the AC output and inactive configurations providing a zero voltage at the AC output;
• wherein a ratio between a total period of time in which the switching device is in an active configuration and a total period of time in which the switching device is in an inactive configuration is the same for each of the plurality of switching periods and is determined according to a desired voltage at the AC output;
• and
• wherein, in each of the plurality of switching periods, there are at least two time periods in which the switching device is in the inactive configuration, and a ratio between those at least two time periods is changed in dependence on temperature associated with the switching device.