Predictive Control of Multi-Phase Motor for Constant Torque Applications

Abstract

Constant torque motors are needed for rotary screw compressors that are used for cooling and other applications. In such systems, the torque demanded by the load is approximately the same over the whole range of mechanical speeds. In this paper, the use of multi-phase induction machines is investigated for this type of application. The requirement of low stator current distortion is considered. A scheduled approach is used to provide the best possible tuning for each operating point, similar to the concept of gain scheduling control. Simulations and laboratory tests are used to assess the proposal and compare it with finite-state predictive control. The experiments show that a trade-off situation appears between the ripple content in stator currents in the torque-producing and harmonic planes. As a consequence, the controller tuning appears as an important step. The proposed method considers various figures of merit with cost function tuning, resulting in a scheduled scheme that provides improved results. It is shown that the approach leads to a reduction in current ripple, which is advantageous for this particular application.

Improving Steady State Accuracy in Field-Weakened Six-Phase Induction Machines with Integrator and Modulated Predictive Control

“…Using (12), it is possible to compute a second step forward prediction of the stator currents îs[k+2|k] for the dead time compensation [27]. The stator current references are represented by i * s[k+2] .…”

“…FCS-MPC offers certain advantages, such as handling multiple targets and constraints, adapting to different power converters or machine models, and controlling linear and non-linear systems. Other types of FCS-MPC have been developed to address their limitations, such as (x − y) current reduction and computational burden reduction [10][11][12][13]. In the realm of FCS-MPC, an eye-catching limitation is the steady-state error.…”

Field-Weakening Strategy with Modulated Predictive Current Control Applied to Six-Phase Induction Machines

“…Numerous FCS-MPC variants have been developed in recent years to address its limitations, such as steady-state tracking error and high computational burden. These variants have shown promising results and can potentially revolutionize the field of multiphase machine control [13][14][15][16][17][18].…”

FCS-MPC Based on Dimension Unification Cost Function

“…Relative to MPTC, this approach minimizes current harmonics and demonstrates broad applicability across power converters and motor drives [8,9]. FCS-MPC stands as a distinct branch within the realm of MPC, distinguished by its ability to meticulously explore all switch states of the inverter and select the optimal switch Energies 2024, 17, 2479 2 of 15 state output based on a defined cost function, thereby offering rapid response dynamics and facilitating multi-objective optimization [10][11][12]. Although FCS-MPC has the ability to achieve multi-objective optimization, it still faces many challenges, such as designing the cost function and selecting weight coefficients [13].…”