Abdelaziz Kheloui

Hybrid Cascaded H-Bridge Multilevel-Inverter Induction-Motor-Drive Direct Torque Control for Automotive Applications

This paper presents a hybrid cascaded H-bridge multilevel motor drive direct torque control (DTC) scheme for electric vehicles (EVs) or hybrid EVs. The control method is based on DTC operating principles. The stator voltage vector reference is computed from the stator flux and torque errors imposed by the flux and torque controllers. This voltage reference is then generated using a hybrid cascaded H-bridge multilevel inverter, where each phase of the inverter can be implemented using a dc source, which would be available from fuel cells, batteries, or ultracapacitors. This inverter provides nearly sinusoidal voltages with very low distortion, even without filtering, using fewer switching devices. In addition, the multilevel inverter can generate a high and fixed switching frequency output voltage with fewer switching losses, since only the small power cells of the inverter operate at a high switching rate. Therefore, a high performance and also efficient torque and flux controllers are obtained, enabling a DTC solution for multilevel-inverter-powered motor drives.

A Comparison of Symmetrical and Asymmetrical Three-Phase H-Bridge Multilevel Inverter for DTC Induction Motor Drives

Earlier studies have pointed out the limitations of conventional inverters, especially in high-voltage and high-power applications. In recent years, multilevel inverters are becoming increasingly popular for high-power applications due to their improved harmonic profile and increased power ratings. Several studies have been reported in the literature on multilevel inverters topologies, control techniques, and applications. However, there are few studies that actually discuss or evaluate the performance of induction motor drives associated with three-phase multilevel inverter. This paper presents then a comparison study for a cascaded H-bridge multilevel direct torque control (DTC) induction motor drive. In this case, symmetrical and asymmetrical arrangements of five- and seven-level H-bridge inverters are compared in order to find an optimum arrangement with lower switching losses and optimized output voltage quality. The carried out experiments show that an asymmetrical configuration provides nearly sinusoidal voltages with very low distortion, using less switching devices. Moreover, torque ripples are greatly reduced.

Virtual-Sensor-Based Maximum-Likelihood Voting Approach for Fault-Tolerant Control of Electric Vehicle Powertrains

This paper describes a sensor fault-tolerant control (FTC) for electric-vehicle (EV) powertrains. The proposed strategy deals with speed sensor failure detection and isolation within a reconfigurable induction-motor direct torque control (DTC) scheme. To increase the vehicle powertrain reliability regarding speed sensor failures, a maximum-likelihood voting (MLV) algorithm is adopted. It uses two virtual sensors [extended Kalman filter (EKF) and a Luenberger observer (LO)] and a speed sensor. Experiments on an induction-motor drive and simulations on an EV are carried out using a European urban and extraurban driving cycle to show that the proposed sensor FTC approach is effective and provides a simple configuration with high performance in terms of speed and torque responses.

A Control Reconfiguration Strategy for Post-Sensor FTC in Induction Motor-Based EVs

This paper deals with experimental validation of a reconfiguration strategy for sensor fault-tolerant control (FTC) in induction-motor-based electric vehicles (EVs). The proposed active FTC system is illustrated using two control techniques: indirect field-oriented control (IFOC) in the case of healthy sensors and speed control with slip regulation (SCSR) in the case of failed current sensors. The main objective behind the reconfiguration strategy is to achieve a short and smooth transition when switching from a controller using a healthy sensor to another sensorless controller in the case of a sensor failure. The proposed FTC approach performances are experimentally evaluated on a 7.5-kW induction motor drive.

Design and control of the induction motor propulsion of an Electric Vehicle

This paper deals with a methodology for presizing the induction motor propulsion of an Electric Vehicle (EV). Based on the EV desired performances, the induction motor optimal power can be calculated. The final objective is to find its minimum weight, volume, and cost that meet the design constraints with minimum power under the European urban (ECE-15) and sub-urban (EUDC) driving cycles. The power presizing methodology is validated through extensive simulations for different induction motor-based EVs using a siding mode control technique.

Discontinuous SVPWM Techniques for Double Star Induction Motor Drive Control

In this paper, we present SVPWM control techniques suitable for a double-star induction motor drive (DSIM). The induction machine has two sets of three-phase stator windings spatially shifted by 30 electrical degrees. Each set of three-phase stator windings is fed by a three-phase inverter. Continuous and discontinuous space vector PWM techniques are presented. Implementation on a DSP controller board is achieved and experimental results on a 15 RW DSIM prototype machine are carried out

An optimal fuzzy logic power sharing strategy for Parallel Hybrid Electric Vehicles

Vehicle emission reduction has been a research objective for many years, by improving fuel economy and energy efficiency. Therefore, this paper presents a fuzzy logic controller for a Parallel Hybrid Electric Vehicle (PHEV). The PHEV required driving torque is generated by a combined contribution from an Internal Combustion Engine (ICE) and an Induction Motor (IM). The proposed Fuzzy Logic Controller (FLC) is designed based on the desired driving torque and the batteries State of Charge (SoC) with the objective to minimize fuel consumption and emissions, while enhancing or maintaining the PHEV driving performance characteristics. The fuzzy controller output controls the ICE throttle angle degree to achieve operation in a high efficiency region. The induction motor is sized to supply peak power to meet the load power requirement of the PHEV. The proposed PHEV fuzzy controller is implemented and simulated via the advanced vehicle simulator ADVISOR using the European urban (ECE-15) and sub-urban (EUDC) driving cycles. Simulation results reveal that the proposed fuzzy torque distribution strategy is effective over the entire operating range of the vehicle in terms of performance, fuel economy, and emissions.

Hybrid cascaded H-bridge multilevel inverter motor drive DTC control for Electric Vehicles

This paper presents a hybrid cascaded H-bridge multilevel motor drive DTC control scheme for electric (EV) or hybrid electric vehicles (HEV). The control method is based on direct torque control operating principles. The stator voltage vector reference is computed from the stator flux and torque errors imposed by the flux and torque controllers. This voltage reference is then generated using a hybrid cascaded H-bridge multilevel inverter, where each phase of the inverter can be implemented using a DC source, which would be available from fuel cells, batteries, or ultracapacitors. This inverter provides nearly sinusoidal voltages with very low distortion, using less switching devices. Due to the small dv/dts, torque ripple is greatly reduced. In addition, the multilevel inverter can generate a high and fixed switching frequency output voltage with less switching losses, since only the small power cells of the inverter operate at high switching rate. Therefore a high performance and also efficient torque and flux controller is obtained, enabling a DTC solution for multilevel inverter powered motor drives.

An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs

This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses.

A 7-level single DC source cascaded H-bridge multilevel inverters control using hybrid modulation

This paper presents a new hybrid cascaded H-bridge multilevel inverter (HCMLI) motor drive DTC control scheme for electric vehicles or hybrid electric vehicles where each phase of the inverter can be implemented using only a single DC source. Traditionally, each phase of the inverter require n DC source for 2n + 1 output voltage levels. In this paper, a scheme is proposed that allows the use of a single DC source as the first DC source which would be available from batteries or fuel cells, with the remaining (n − 1) DC sources being capacitors. This scheme can simultaneously maintain the DC voltage level of the capacitors, produce a nearly sinusoidal output voltage due to its high number of output levels and therefore a high performance and also efficient torque and flux controller is obtained, enabling a DTC solution for hybrid multilevel inverter powered motor drives.