Performance Analysis of Direct Torque Controllers in Five-Phase Electrical Drives

Abstract

The industrial application of electric machines has grown in the last decades, thanks to the development of microprocessors and power converters, which have permitted their use as variable-speed drives. Although three-phase machines are the common trend, the interest of the research community has recently focused on machines with more than three phases, known as multiphase machines. The principal reason lies in the exploitation of their advantages in terms of reliability, i.e., post-fault operating capability. Additionally, multiphase machines provide a better current distribution among phases, and lower current harmonic production in the power converter, than conventional three-phase machines. However, multiphase drive applications require the development of complex controllers to regulate the torque (or speed) and flux of the machine. In this regard, direct torque controllers have appeared as a viable alternative due to their easy formulation and high flexibility to incorporate control objectives. However, these controllers face some peculiarities and limitations in their use that require attention. This work aims to tackle direct torque control as a viable alternative for the regulation of multiphase drives. Special attention will be paid to the development of the control technique and the expected benefits and limitations in the obtained results. Case examples based on symmetrical five-phase induction machines with distributed windings in the motoring mode of operation will be used to this end.

Analysis of the Efficiency of Traction Drive Control Systems of Electric Locomotives with Asynchronous Traction Motors

“…The character of the variation of the stator phase currents in the vector control (Figure 6a) corresponds to the character of the stator phase currents presented in works [6][7][8], which are dedicated to the investigation of the operation of the system with asynchronous motor vector control. The character of the variation of the stator phase currents in the direct torque control (Figure 6b) corresponds to the character of the stator phase currents presented in works [9][10][11], which are dedicated to the investigation of the operation of the system with an asynchronous motor and direct torque control of the asynchronous motor.…”

“…Systems with a scalar [4,5], vector [6][7][8], and direct torque control [9][10][11] are used as electric traction drive control systems for asynchronous traction motors.…”

Simulation of a direct torque control system in the presence of winding asymmetry in induction motor

“…In modern electric transport, squirrel-cage induction electric motors have become the most widespread as traction electric motors [1][2][3]. To control them, systems built using scalar [4,5], vector [6][7][8] and direct torque control (DTC) [9][10][11] are used.…”

“…When constructing a classical DTC [9][10][11], the hypothesis that the arms of the inverter and the motor windings are symmetrical is used. This leads to the fact that when determining such parameters of the control system as the modulus and angle of the stator flux coupling and the value of the torque, errors occur.…”

Instantaneous Reactive Power Theory in the Geometric Algebra Framework

“…The latter can be considered of great importance, since drives with more than three phases have emerged in recent years. In effect, the control of 5-phase, 12-phase, or 16-phase motors in wind turbine or electric vehicle applications is an ongoing field of research [25,26].…”