Optimized Field-Weakening Strategy for Control of PM Synchronous Motors

Field-weakening mode of operation is an important feature of modern permanent magnet (PM) synchronous electrical drives, which overcomes speed limitation due to the lack of supplying voltage and increases their speed operational range. Therefore, field-weakening (FW) algorithm is an inalienable part of the overwhelming majority of control systems for PM synchronous motors. At the same time, seamless integration of the filed-weakening techniques into the conventional control systems is not considered well and some reported solutions may decrease system reaction time and cause stability issues. This paper proposes an improved field-weakening strategy, which includes optimized FW controller and novel current limitation strategy in the field-weakening mode. These features simplify structure of the resulting control scheme, decrease computational burden on the microcontrollers and decreases system reaction time, caused by wind-up of the speed controller operating in parallel with the conventional FW algorithms.