Increasing the efficiency in buck-boost Y-voltage source inverter (Y-VSI) can happen by reducing the switching losses. This paper proposes a new soft-switching method to achieve minimum switching losses in Y-VSI. First, switching inductor current boundaries are found using the current equation in both buck and boost chopping operation. To minimize the required deadtime for capacitor discharging between turn on and turn off of the switches, an adaptive deadtime is calculated for both lower and upper boundaries of the inductor current. Using calculated deadtime for turn on and turn off in the switches, variable frequency pulse width modulation (PWM) signals are used to achieve full zero voltage switching (ZVS) range for both buck side and boost side switches in Y-VSI. Simulation results verify that the proposed ZVS method increases efficiency more than %2 in a 5 kW SJ-based Y-VSI.

This article presents an improved Hamiltonian control law (HCL) with load current sensorless ability for multiphase parallel converters in electric vehicle applications. On one hand, the proposed control approach has a significant advantage in handling constant power load (CPL) that occurs in the situation of the vehicle, which is a dangerous situation that can cause oscillations and uncertainty. On the other hand, the load current observer is applied with HCL to improve the efficiency and reliability of the converter system. In addition, by eliminating the need for current sensors, the cost and size of the converter system are reduced, while maintaining accurate current control. Moreover, the difference flatness approach has been applied to generate the current reference resulting in regulating the DC bus voltage. Finally, the multiphase two-quadrant converter driving by the proposed control law has been evaluated through experimental tests. The obtained experimental results demonstrate the excellent performance of the multiphase two-quadrant converter with CPL thereby confirming the efficacy of the proposed approach.

The inherent high nonlinearity of Switched Reluctance Machines (SRMs) poses significant challenges to modeling. Conventionally, large-data-size lookup tables (LUTs) are used, which consume extensive storage space in digital signal processors (DSPs) and complicate the application of well-established PI control techniques. This paper presents a linear flux SRM model, leveraging the space mapping method to map the SRM's nonlinear flux profile into a linear space in relation to both current and position. The proposed linear model offers two key advantages. First, it reduces data storage needs due to smaller LUTs. Second, it enhances the feasibility of applying PI control. Simulation results of an 8/6 SRM are presented to illustrate the proposed approach.

The vibration/noise and torque ripple are two inherent issues for switched reluctance motors (SRMs), one of the effective methods to address these two issues is flattening both the total radial force and total torque. In this paper, an optimized quadratic-sharing-function-based radial force and torque simultaneous flattening method is proposed for SRMs. Firstly, the features of the radial force and torque characteristics are analyzed without considering saturation. Then, with these unique and specific features, four regions are defined to develop the simultaneous radial force and torque control method based on the linear sharing functions. To incorporate the saturation effects in the proposed method, the quadratic sharing functions are adopted. The proper parameters of the quadratic sharing functions and the region definition at different operating conditions are obtained through the genetic algorithm (GA) optimization. The switching angles and reference current of the conventional current chopping control (CCC) method are also optimized by GA for fair comparison purpose. Extensive simulation results are presented in this paper, and these results prove the effectiveness and superiority of the proposed method regarding the simultaneous radial force and torque control.

This paper presents a high frequency linear model for low-speed sensorless control of interior permanent magnet synchronous motor (IPMSM) drives. The proposed model uses a β-axis high frequency signal injection in order to model a new high frequency flux variable, which has similar properties to the standard electromotive force (EMF) used for high-speed sensorless control. Through the proposed model, the well established observer techniques from the literature can be used for rotor position and speed estimation. Thus, the low-speed sensorless scheme can be designed in similar form as the high-speed EMF based methods. Here, position and speed estimation are performed by an adaptive full-order observer, which is designed through a pole placement method and its stability constraints are investigated. Simulation results validate the proposed high frequency linear model and adaptive observer design method under sensorless vector control.

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Proper current control is essential in SRM drives in order to ensure adequate reference tracking and torque ripple reduction when using current profiling techniques. In this context, this paper proposes a PWM super-twisting sliding mode current controller for switched reluctance motors with a fixed-gain structure. The approach presents a model-free structure, not requiring model information on implementation. The PWM implementation ensures a fixed switching frequency and the fixed-gain approach leads to a simple control structure, not demanding any sort of gain lookup tables. The complex task of gain design for super-twisting controllers is solved in this paper by means of an optimization-based design methodology, using the sum of the squared error as a cost function. The proposed technique is compared to a higher sampling hysteresis controller in terms of current and torque root-mean-square error. Simulation results are presented, showing that the proposal achieves a performance comparable to a higher sampling hysteresis controller.

A simplified space-vector pulse width modulation based overmodulation technique for permanent magnet synchronous motor drive system is proposed. There are two overmodulation modes in the proposed method. The duties of two modes for overmodulation region in modulation hexagon sector one are generated by simplified linear formulae. With simplified linear duty generating formulae, the computational burden is relatively smaller than conventional overmodulation method. DC bus voltage is maximum utilized and modulation index can be extended to the maximum value. The transition between linear modulation and overmodulation, and overmodulation and six-step operation is smooth. The results of verification on a PMSM platform demonstrate the effectiveness of the proposed method.

In this paper, a virtual-flux finite control set model predictive control (MPC) strategy for dual three-phase interior permanent magnet synchronous motors (DTP-IPMSM) is proposed. The technique is based on the conventional predictive current control, but it maps the measured variables into a virtual- flux domain, thus simplifying the prediction stage. The technique uses a flux-based cost function to track the estimated reference flux. The flux tracking cancels out to guarantee an improved current tracking, and thus, a better torque ripple. The proposed technique is validated through simulation of a 100 kW DTP- IPMSM in Matlab/Simulink. Results evidenced a reduced current control error, thus improving the torque tracking up to 38.9 % when compared to the conventional inductance based model predictive control.

This paper presents a novel self-commissioning procedure for the identification of inverter nonlinearity constant comprised of the average voltage drops on switches and diodes in conduction state and switching delays. Simultaneous estimation of phase resistance, d-axis synchronous inductance, and inverter nonlinearity constant is achieved at standstill condition by injecting sinusoidal d-axis current. The advantages of the proposed self-commissioning method are twofold: 1) The co-estimation capability provides insensitivity towards errors in resistance and d-axis inductance. 2) While sinusoidal d-axis current is injected, the q-axis current is actively maintained at 0A. Thus, no torque is generated during the self-commissioning period. The effect of discontinuous distortions due to non-ideal switching as well as current sensor noise is rejected by limiting the estimation period within a feasible estimation window. Thereby, a necessary minimum phase current magnitude is established for achieving accurate estimation. This paper also provides parameter convergence analysis and the existence of unique solutions during proposed self-commissioning process, further justifying the choice of proposed feasible estimation region.

This paper analyzes permanent magnet synchronous machines (PMSM) under open phase and phase-to-phase fault conditions within an electric vertical take-off and landing (eVTOL) aircraft. The development of a detailed mathematical model for a PMSM under the open phase fault (OPF) and phaseto-phase short circuit fault (P2PSCF) conditions are presented and implemented in MATLAB/Simulink along with its results within a ring bus electrical distribution system (REDS) for an eVTOL is presented. The behavior of both faults is investigated. Fault-tolerant control (FTC) is applied during the post-fault operation, and the copper losses and torque ripple are analyzed. Two fault mitigation techniques, 1) disabling the inverter (FTC1) and 2) creating a virtual neutral point (FTC2) with the inverter, are introduced for the P2PSCF. FTC1 had a peak-to-peak torque ripple of 309Nm with 1.55kW reduction of copper losses. FTC2 was found to respond faster than FTC1 and generated 157Nm peak-to-peak torque ripple. The OPF FTC was analyzed where only current references are changed for the same PI controller structure to enable a fail-operational state for the eVTOL. The OPF FTC achieved 348Nm peak to peak torque ripple compared to 371Nm to pre-fault conditions.

This paper proposes an adaptive voltage regulation (VR) flux-weakening (FW) control technique for dual three-phase (DTP) permanent magnet synchronous machine (PMSM) drives. Firstly, a small-signal model is developed to demonstrate the need of gain adaptation in order to maintain the controller bandwidth. Moreover, the small-signal model serves as a tuning tool for the FW proportional-integral (PI) controller. Then, the proposed adaptive controller is implemented and tested on a 100 kW DTP-PMSM drive. Simulation results demonstrate an improved drive performance at high speeds when benchmarked against non-adaptive controllers. Furthermore, the adaptive controller offers an extended speed range.

An adaptive gain for voltage controller in fluxweakening control of permanent magnet synchronous motor (PMSM) is proposed. Based on voltage angle control scheme, voltage feedback controller can adjust control current locus and utilize the DC link voltage in flux-weakening region. The voltage controller is controlled using the difference between voltage reference magnitude and and a proper inverter limit value. The analysis of voltage controller is carried out, taking into account of modulation delay to issue the compensation performance with different voltage feedback gains from difference PMSM operating conditions. The adaptive gain of voltage controller is applied with forward feedback voltages and current vector to improve dynamic response with smaller voltage errors. The results of verification on a 7-kW PMSM platform demonstrate the effectiveness of the proposed method.

Nowadays distribution power systems are used in different applications such as aircraft, ships, submarines and hybrid electric vehicles. However, the interaction between individually designed power subsystems may cause instability. Moreover, in these applications, the constant power load (CPL) also poses challenges for system dynamic response and stability. Thus, the main objective is to stabilize the cascaded system supplying the CPL. An interconnection and damping assignment (IDA) passivity-based control (PBC) scheme for LC filter cascaded with buck converter supplying CPL is proposed. The plant is described by port-controlled Hamiltonian (PCH) form. Particularly, an adaptive interconnection matrix is developed to achieve internal links in PCH system. A modified IDA-PBC and its proof are presented to perfect the implementation for the CPL application. Simulation results are given to illustrate the effectiveness of the proposed approach.

The automatic diagnosis of systems is essential in several industries such as aeronautics. This paper introduces a method to diagnose systems with respect to the constraints of the aeronautics field: robustness and low computation costs. The proposed methodology is based on the combination of Support Vector Machine and Fuzzy Membership Functions (SVM-MBF). The distances, which are computed by the SVM, are fuzzified in order to give a degree of confidence in the classification. Besides, using SVM-MBF allows estimating the severity of a fault. The architecture of the proposed diagnosis system consists in putting in series one classifier to detect faults, with a set of classifiers, one per fault, to assess the severity. The method is applied to the diagnosis of inter-turn short-circuits of a Permanent Magnet Synchronous Machine (PMSM). The data come from measurements performed on a machine designed for aeronautics applications. The method is evaluated in terms of robustness and computation time by using cross validation. The results show the suitability of the methodology for aeronautics applications and to the path of onboard diagnosis algorithm.

It is well know that the interaction between poorly damped LC input filter with dc-dc converter lead to degradation of dynamic performance and fault scenario of the system. This problem also often occurs in fuel cell systems. Due to the relatively low and unregulated output voltage, the high gain boost converter is need in such application. A floating interleaved boost converter (FIBC) is selected as a good candidate to achieve this desired effect. In order to ensure the system stability, this paper addresses a method which permits to design a fault-tolerant stabilizing system for the proposed converter and the filter. It consists in implementing an active stabilizer for each switch. Afterward, a method to design fault-tolerant stabilizing system is developed. The simulation results are reported to verify the effectiveness of the proposed method.

This paper presents the low speed position estimation scheme for an IPM machine controlled by model predictive control with finite control set. The career signal injection is not viable as there is no PWM to superimpose it with PWM for this type of control. The pulse vector injection technique requires current derivative sensors which makes the overall scheme less attractive. This paper utilizes the inherent high frequency vector injection of the model predictive control to extract the position information. It is shown that the high frequency current response is amplitude modulated with respect to the position. A demodulation technique based on the reactive power estimation is proposed. The simulation results at various initial positions confirm the validity of the proposed position estimation scheme.

The electric vehicle technology has been adopting PEM fuel cells for hybrid applications over the past decades. Fuel cell systems are often low voltage systems. The key requirements of a boost converter for such application are need of high-voltage. The second-order low-pass filter is often used to filter the high frequency current ripple. It is known that the interaction between the poorly damped filter with the converter leads to degradation of dynamic performance and instability of the system. This paper addresses a novel wide stability control strategy to solve this problem without increasing the weight and size. In this paper, the mathematical model of the system is built. The dynamic stability of the system is investigated based on root locus and Lyapunov first method. The simulation results are reported to verify the effectiveness of the proposed method.

Power electronic converters and electric motor drives have become common loads in advanced power systems. Passive LC filters are often used in these systems to reduce the DC-link ripples. These filters are poorly damped for reducing the power losses as well as the size, weight and cost of the system. This may lead to instability phenomena if the load is tightly controlled and absorbs a power exceeding a limit depending on the filter parameters. The purpose of this paper is to present an input impedance shaping method to stabilize DC-link. A matrix filter is put in cascade with load's current controllers. The filter is designed to shape properly input impedance of the load while keeping its performances. Small signal stability of the DC power system is proved using this method. Simulation and experimental results confirm the effectiveness of the proposed stabilizer.

In this paper, a global optimal study of the efficiency of a cascaded structure with synchronous rectification composed of two sub-converters has been presented, this converter allows obtaining high voltage ratio and consists of two-interleaved boost converter which was chosen as 1stsub-converter and three-level boost converter which was chosen as 2ndsub-converter. An optimal efficiency operation as a function of the intermediate voltage and the branch number of the first converter is studied by the aid of an adaptive losses estimation algorithm to estimate the components losses for each DC/DC converter. The estimated power losses of the two converters are modeled by two estimated resistances. These estimated resistances are used to study and optimize the relation between the intermediate voltage and the global efficiency and also the influence of the number of branches of the interleaved converter on the total global losses. The algorithm is theoretically analyzed, developed and compared with the experimental results. Experimental results allow validating the proposed analysis for maximizing global efficiency.

This article presents a new position and speed sensorless drive for non-salient pole PM synchronous machines in low speed range including standstill. The proposed method does not depend on the machine parameters and is very simple to implement. A voltage pulse injection is combined to a magnetic circuit saturation which will be created by an additional current. This latter is not necessary if the machine is salient pole. Mathematical proof of the convergence is presented. The minimum saliency required for sensorless operation at zero speed is determined. It is also shown that the proposed approach is robust with respect to parameter uncertainties. The effectiveness of this technique is verified by simulation and experimentation on an eight-poles 1 hp - 1000 rpm test machine.