Fast model predictive pulse pattern control

A non-transitory computer-readable medium configured with instructions executable by a computer to control an electrical converter to:

• determine an error value based on a difference between an estimated output value and a reference output value, the estimated output value being based on measurements in the electrical converter;
• compare the error value with an error band and in the case of the error value being within the error band, controlling the electrical converter with a modified pre-calculated switching sequence by:
• determining a pre-calculated switching sequence for the converter based on an actual state of the electrical converter, the switching sequence comprising a sequence of switching transitions of the converter,
• modifying the pre-calculated switching sequence by modifying transition times of switching transitions of the pre-calculated switching sequence, such that the error value is minimized,
• applying at least a part of the modified switching sequence to the electrical converter, and
• in the case where the error value exceeds the error band, controlling the electrical converter by switching to a different control scheme, wherein the different control scheme is based on inserting an additional switching transition into the pre-calculated switching sequence before the pre-calculated switching sequence is modified and the additional switching transition generate an additional pulse with an infinitesimal small width;
• and
• select an error band associated with the error value from a plurality of error bands, whereby a voltage level of the inserted switching transition is dependent on the determined error band and a selection of an error band is based on past error values.

An electrical converter, comprising:

• a plurality of semiconductor switches;
• and
• a controller adapted for controlling the semiconductor switches;
• wherein the controller is structured to execute instructions stored in a non-transitory computer readable medium to control the converter to:
• determine an error value based on a difference between an estimated output value and a reference output value, the estimated output value being based on measurements in the electrical converter;
• compare the error value with an error band and in the case of the error value being within the error band, controlling the electrical converter with a modified pre-calculated switching sequence by:
• determining a pre-calculated switching sequence for the converter based on an actual state of the electrical converter, the switching sequence comprising a sequence of switching transitions of the converter,
• modifying the pre-calculated switching sequence by modifying transition times of switching transitions of the pre-calculated switching sequence, such that the error value is minimized,
• applying at least a part of the modified switching sequence to the electrical converter, and
• in the case where the error value exceeds the error band, controlling the electrical converter by switching to a different control scheme, wherein the different control scheme is based on inserting an additional switching transition into the pre-calculated switching sequence before the pre-calculated switching sequence is modified and the additional switching transition generate an additional pulse with an infinitesimal small width;
• and
• select an error band associated with the error value from a plurality of error bands, whereby a voltage level of the inserted switching transition is dependent on the determined error band and a selection of an error band is based on past error values.