TWO-DIMENSIONAL VARIABLE LIMIT PROPORTIONAL INTERNAL REGULATOR FOR THE CURRENT CONTROLLER IN SYNCHRONOUS FRAME

摘要

A controller (400) for a variable-speed induction motor (498) includes field-oriented control (410, 476), which in a feedback (402) arrangement senses motor parameters to form field and torque error signals. The field error signals are processed by a first limited-state PI processor (490a), which individually limits the magnitude of the proportional component of the field voltage to no greater than the bus voltage. The field error signals are also processed by a state-limited integrator (426a) which limits the integral component of the field voltage to the difference between the proportional component and the bus voltage. A first summer (432a) sums the proportional and integral components to make the field voltage command. The torque error signals are processed by a further limited-state PI processor (490b) which individually limits the proportional component of the torque voltage to a value not greater than the available bus voltage, after the first PI processor has been given preference. The integral component of the torque voltage command is generated by a second state-limited integrator (426b) which limits the integral component of the torque voltage command so that the torque voltage command does not exceed the available bus voltage. A second summing circuit (432b) sums the proportional and integral components of the torque voltage command. The field and torque voltage commands are processed to produce the desired motor flux and torque, and a feedback loop forces the motor current to follow the commanded values.