Closed-loop Torque Control of an Absorbing Dynamometer for a Motor Test-Bed

In order to test control algorithms for DC and AC motors, under a variable speed configuration, is necessary to provide a regulated load torque. Moreover, it is desirable to adjust on-line this quantity in order to simulate practical scenarios and nonlinear loads. Thus, with this objective in mind, the design and closed-loop torque control strategies for an absorbing dynamometer are detailed in this paper. This device is constructed using a permanent-magnet DC motor and a two-quadrant DC-DC chopper, and it is designed to operate independently of the motor velocity orientation. Two nonlinear control schemes are presented to regulate accurately the torque provided by the dynamometer. Finally, simulation and experimental results are illustrated for a 2HP DC motor test-bed.