This paper analyzes the effects of the rotor position error in the performance of field-oriented-controlled permanent-magnet synchronous machine (PMSM) drives intended for electric vehicle (EV) traction applications. A special focus is given to the torque ripple generated along the characteristic trajectories in the different operating regions of the PMSM. An extended and generalized model of the torque ripple produced by the PMSM as a function of the rotor position error is analytically deduced. An infinite-speed interior-(I)PMSM drive and a finite-speed surface-mounted (SM)-PMSM drive are considered for the simulations carried out in MATLAB-SimPowerSystems. The experimental results have been validated with a TM4 EV drive controlling an 80-kW SM-PMSM. The torque ripple has been evaluated for both motoring and regenerative braking operation modes under maximum torque conditions going from 100 N · m at 1000 r/min up to 55 N · m at 9000 r/min. The obtained simulation and experimental results demonstrate the good accuracy of the proposed model for evaluating the torque ripple produced in PMSMs due to the error from the rotor position sensor.

This paper presents a novel algorithm based on polynomial approximations (PAs) for an efficient error compensation of magnetic analog encoders (MAEs) in permanent-magnet synchronous machines (PMSMs) intended for electric vehicle (EV) propulsion. The proposed PA algorithm requires a negligible memory space compared to a very high-resolution look-up table (LUT). The use of polynomials allows compensating every possible input rotor position without carrying out an interpolation or a rounding to the nearest quantized value. The PA algorithm has been implemented to work in real time on a TM4 EV drive controlling an 80 kW PMSM. The performance of the algorithm has been validated at 6000 and 9000 r/min under +85 and ±55 Nm of torque, respectively. The electromagnetic interference (EMI) effects have been minimized using a type-2 phase-locked loop (PLL). The proposed PA algorithm assisted with the PLL is capable of reducing the total position error to a range as small as ±0.2°. The combination of these two algorithms is a promising solution for compensating the position error in quadrature analog encoders. The experimental results obtained with the 80 kW PMSM demonstrate the feasibility of low-cost MAEs for achieving high-performance field-oriented control (FOC) of PMSMs in EV drives.

This paper investigates the performance of two novel half-switching frequency signal injection (HSFSI) demodulation algorithms for encoderless field-oriented control (FOC) of permanent magnet synchronous machines (PMSMs) intended for electric vehicle (EV) propulsion. The proposed rotating and pulsating HSFSI demodulation algorithms do not require voltage measurements or approximations for estimating the rotor position angle. The proposed HSFSI algorithms have been quantitatively and qualitatively compared by MATLAB-SimPowerSystems simulations, as well as experimentally against the two equivalent classical high-frequency signal injection (HFSI) approaches. A 2.5 kW PMSM with radially inset rotor magnets has been used for experimentally evaluating and validating the performance analysis and the comparison of the four algorithms fully implemented to work in real-time on a TI C2000 digital signal processor (DSP). The results obtained with an 80 kW interior (I)-PMSM intended for EV propulsion also show that the proposed algorithms allow a better machine control performance in terms of a smaller torque ripple generation and a faster current control loop.

This paper analyses the position error compensation in quadrature analog magnetic encoders through the iterative linear search optimization algorithm of "steepest descent". In current literature, the sine/cosine signals from the encoder are compensated considering only the gain mismatch, the DC offset components and the non-orthogonality. Nevertheless, the magnetic field distortion due to the non-homogeneity of the magnet and the distortion of the signals due to the mechanical misalignment between the rotation axis of the motor shaft, the magnet center and the chip sensor are generally neglected. In this work, all of these factors are taken into account. The results show that a higher order approximation for modeling the harmonic distortion contained in the encoder signals leads to a slight biasing in the convergence of the compensating parameters. However, the unconstrained and multivariate optimization algorithm of steepest descent fairly minimizes the error from the objective function F(x_n) allowing achieve a compensation efficiency of up to 66%, thus increasing the overall accuracy of this kind of magnetic encoders and improving the performance of any application where they provide rotary position feedback.

This paper presents the performance evaluation of a proposed single-phase bidirectional active neutral-point-clamped (ANPC) five-level converter (5LC) for active filtering in grid-to-vehicle (G2V), vehicle-to-grid (V2G) and vehicle-to-home (V2H) applications. In the system, the 5LC is series-connected with an electric vehicle battery charger based on a dual active half-bridge DC-DC converter (DAHBC). A cascaded strategy with a proportional-resonant compensator controls the 5LC whereas the DAHBC is controlled by a single phase-shift technique. A performance comparison is carried out for the proposed topology versus three NPC/ANPC 5L converters found in literature with similar topologies. The simulation results obtained in MATLAB-SimPowerSystems along with the experimental results obtained from a laboratory prototype validate the following: a) the first two literature topologies have the highest efficiencies, but they are incapable of balancing the voltage of the split-capacitors what increases the total harmonic distortion of both the grid current in the G2V/V2G modes and the 5LC output voltage in the V2H mode while producing a sluggish transient response, b) the 3rd literature topology like the proposed one properly balance the capacitors voltage and achieve a faster dynamics, but at the expense of an efficiency reduction, and c) unlike the former topology that continuously applies a natural but wasting unfedback voltage balancing strategy, the proposed one that includes a closed-loop control allows achieving an ANPC 5LC with a superior performance featured by a higher efficiency, a reduced switches stress, a flatter power losses distribution and a better power quality improving under the three modes of operation.

This paper presents a multi-objective design optimization of a power transformer to find the optimal geometry of its core and the low- and high-voltage windings, representing the minimum power losses and the minimum core and copper weights. The optimal design is important because it allows manufacturers to build more efficient and economical transformers. The approach employs a manufacturer’s design methodology, which is based on the usage of the laws of physics and leads to an analytical transformer model with the advantage of requiring a low amount of computing time. Afterward, the multi-objective design optimization is defined along with its constraints, and they are solved using the Non-Sorting Genetic Algorithm III (NSGA-III), which finds a set of optimal solutions. Once an optimal solution is selected from the Pareto front, it is necessary to fine-tune it with the 3D Finite Element Analysis (FEA). To avoid the large computing times needed to carry out the 3D Finite Element (FE) model simulations used in multi-objective design optimization, Response Surface Methodology (RSM) polynomial models are developed using 3D FE model transformer simulations. Finally, a second multi-objective design optimization is carried out using the developed RSM empirical models that represent the cost functions and is solved using the NSGA-III. The numerical results of the optimal core and windings geometries demonstrate the validity of the proposed design methodology based on the NSGA-III. The used global optimizer has the feature of solving optimization problems with many cost functions, but it has not been applied to the design of transformers. The results obtained in this paper demonstrate better performance and accuracy with respect to the commonly used NSGA-II.