PMSM Field-Weakening Control
This example shows how to control the rotor angular velocity above the nominal velocity in a permanent magnet synchronous machine (PMSM) based electrical-traction drive. A high-voltage battery feeds the PMSM through a controlled three-phase converter. The Control subsystem includes a multi-rate PI-based cascade control structure which has an outer angular-velocity-control loop and two inner current-control loops. The velocity controller generates a torque reference. A zero d-axis controller converts this torque reference to current references. A field weakening controller adjusts the current references to satisfy the voltage constraints above the nominal velocity. A Stateflow® state machine implements the task scheduling in the Control subsystem. During the one-second simulation, the angular velocity demand is 0 rpm, 1800 rpm, 2600 rpm, and then 3300 rpm. Above 1630 rpm, the PMSM enters in field weakening mode. The Scopes subsystem contains scopes that allow you to see the simulation results.
Simulation Results from Simscape Logging
The plot below shows the requested and measured speed for the test, as well as the phase currents in the electric drive.