Sliding mode approach applied to sensorless direct torque control of cage asynchronous motor via multi-level inverter

Abstract

To improve the robustness and performance of the dynamic response of a cage asynchronous motor, a direct torque control (DTC) based on sliding mode control (SMC) is adopted to replace traditional proportional-integral (PI) and hysteresis comparators. The combination of the proposed strategy with sinusoidal pulse width modulation (SPWM) applied to a three-level neutral point clamped (NPC) inverter brings many advantages such as a reduction in harmonics, and precise and rapid tracking of the references. Simulations are performed for a three-level inverter with SM-DTC, a two-level inverter with SM-DTC and the three-level inverter with PI-DTC-SPWM. The results show that the SM-DTC method achieves better performance in terms of reference tracking, while adoption of the three-level inverter topology can effectively reduce the ripples. Applying the SM-DTC to the three-level inverter presents the best solution for achieving efficient and robust control. In addition, the use of a sliding mode speed estimator eliminates the mechanical sensor and this increases the reliability of the system.

An Improved Direct Power Control for Doubly Fed Induction Generator

“…Direct Power Control (DPC) technique can provide DFIG with direct power regulation capability. It avoids PLL and complex parameters tuning in the traditional VOC, which has been widely discussed in recent years [11]- [21]. The conventional DPC utilizes a Look-Up Table (LUT) structure to select switching signals [11].…”

“…It obtains a fast power convergence speed and a high robust property against DFIG parameters mismatch. However, it usually brings a power chattering problem [21], [27]. A Back-Stepping (BS) algorithm combined with direct power control is developed in [18], which has a simple structure and obtains satisfactory steady-state performance.…”

An Intelligent Control Strategy for a Highly Reliable Microgrid in Island Mode

“…Power electronic inverters play more and more important roles in many research fields like motor-driven machines, microgrids, photovoltaics (PVs) and so on [1][2][3][4][5]. One of the basic reasons is the increasing incorporation of direct current (DC)-based renewable energy sources (RES) and storage (PVs and batteries) in the grid, for environmental purposes.…”

Impedance Analysis of Voltage Source Converter Using Direct Power Control

“…The DPC has been proposed for years [22]- [29]. It has fast transient dynamics and usually does not need grid synchronization.…”

“…Recently, some studies have proposed to combine the DPC strategy with Pulse Width Modulation (PWM), which obtains a constant switching frequency [23]. Sliding Mode Control (SMC)-DPC [24], [29] and passivitybased control (PBC)-DPC [25] were designed for VSCs, which improves the system robustness against parameter mismatch. However, the SMC-DPC usually brings power chattering problem.…”