Systems and methods for controlling motor torque output

Abstract

Systems and methods are disclosed for controlling a torque output by an AC motor drawing power from a DC bus. According to certain embodiments, the system for controlling the torque output has a controller and an inverter. The controller further has an operation status detector, a basic voltage vector calculator, and a voltage command generator. The operation status detector is configured to determine a DC bus voltage and a rotor field vector. The basic voltage vector calculator is configured to calculate a plurality of basic voltage vectors having a magnitude proportional to the DC bus voltage. The voltage command generator is configured to generate a voltage command for producing a stator field vector. Producing the stator field vector includes at least one of maintaining a constant angle between the stator field vector and the rotor field vector, and setting a magnitude of the stator field vector equal to the magnitude of the plurality of basic voltage vectors. The inverter is electrically connected to the controller and configured to receive the voltage command. The inverter is also configured to convert the DC bus voltage to one or more AC voltage signals according to the voltage command. The inverter is further configured to apply the one or more AC voltage signals to the AC motor to produce the stator field vector.