Mechanical Domain

Motor Drive with Failure Modes

This PLECS demo model examines a current-controlled permanent magnet machine under several drive fault mitigation strategies. The system includes an inverter with field-oriented control (FOC) that supplies the machine operating at a constant speed. Fault conditions such as loss of auxiliary power supply or microprocessor trip can result in loss of power to the inverter. Usually under such faults, the power stage is disabled. However, when operating in flux-weakening mode, a fault mitigation strategy may be required as the rectified back-emf may be larger than the DC-link voltage. In this simulation, failure mitigation strategies by closing all the lower inverter switches or opening the battery pack contactor are investigated.

Servo Drive with Optimum Braking

This PLECS demo model illustrates a servo drive application, combining the PLECS electrical, control and mechanical domains. The system includes an inverter with field-oriented control that supplies a servomotor coupled to a ball screw gear. The output of the gear is attached to a slide, which holds the part that is being position-controlled for manufacturing (e.g. milling) operations.

DFIG Wind Turbine System

The doubly-fed induction generator (DFIG) system is a popular system in which the power electronic interface controls the rotor currents to achieve the variable speed necessary for maximum energy capture in variable winds. Because the power electronics only process the rotor power, typically less than 25% of the overall output power, the DFIG offers the advantages of speed control with reduced cost and power losses. This PLECS demo model demonstrates a grid-connected wind turbine system using all of PLECS' physical modeling domains. The system model includes a mechanical model of the blades, hub, and shaft, a back-to-back converter including thermal loss calculations, a magnetic model of the three-phase transformer, and the transmission line and grid.