Search Results (644)

To suppress current and torque ripples, this paper proposes a novel deadbeat predictive current control strategy based on an adaptive sliding mode observer for permanent magnet-assisted synchronous reluctance motor (PMa-SynRM) drives. The parameter sensitivity of predictive current control is analyzed, and a sliding mode observer is employed to calculate the parameter disturbances for voltage compensation. The predicted current is utilized instead of the sampled current to address the one-step delay issue, effectively suppressing the adverse effects of parameter mismatch in predictive control. The adaptive control parameter module suppresses the chattering phenomenon in sliding mode control and enhances the observer’s adaptability under varying load conditions. The effectiveness of the proposed strategy is validated on a 2.2 kW PMa-SynRM platform. This strategy can suppress current and torque fluctuations under complex operating conditions, which has significant implications for electric vehicle drive control. Full article

In this article, a new high step-up interleaved DC–DC converter is presented for renewable energy systems. The converter circuit is based on the interleaved two-phase boost converter and integrates a voltage-lift capacitor and a voltage multiplier cell. A high voltage gain of the converter can be achieved with a reasonable duty ratio and the voltage stresses of semiconductor devices are reduced. Because of low voltage stress, the switches with low on-resistance and the diodes with low forward voltage drops can be adopted to minimize the conduction losses. Additionally, the switching losses are reduced because the switches are turned on under zero-current switching (ZCS) conditions. Due to the existence of leakage inductances of the coupled inductors, the diode reverse-recovery problem is alleviated. Moreover, the leakage energy is recycled and the voltage spikes during switch turn-off are avoided. The parallel input architecture and interleaved operation reduce the input current ripple. The operating principles, steady-state characteristics, and design considerations of the presented converter are proposed in detail. Furthermore, a closed-loop control is designed to maintain a well-regulated output voltage despite variations in input voltage and output load. A prototype converter with a rated 1000 W output power is realized for demonstration. Finally, experimental results show the converter effectiveness and verify the theoretical analysis. Full article

Owing to their high performance and high-efficiency controllability, surface-mounted permanent magnet synchronous motors (SPMSMs) have been widely considered for various robotic systems. The conventional three-vector-based model predictive torque control (MPTC) is frequently applied to SPMSMs, while the adjustment of weight factors is difficult. Compared with the five-segment sequence output method, the three-segment sequence output method can effectively reduce the switching frequency. However, the three-segment sequence output method leads to large torque and stator flux ripple. For these issues, a three-vector-based smart MPTC method based on the optimal vector sequence optimized by a genetic algorithm is proposed. Firstly, the reference voltage vector output from the discrete-time sliding mode (DTSM) current controller is utilized to simplify the process of selecting the vectors, and it can enhance the robustness of the SPMSM system. Secondly, an improved cost function is employed to select the optimal vector sequence, aiming to minimize torque and flux ripple. Furthermore, the multi-objective genetic algorithm is leveraged to seek the Pareto solution for weight factors. As a final step, the efficacy of the designed MPTC approach is confirmed through simulations and experiments. Full article

A Buck converter in the DC microgrid is often used to transform high DC voltage to meet the requirements of low voltage loads, where electrolytic capacitors are commonly regarded as the most vulnerable components. A lot of studies have shown that equivalent series resistance (ESR) is the best health indicator for electrolytic capacitors, which means that it is significant to monitor the variation in ESR values for health evaluation. This paper presents a non-intrusive online ESR estimation method of the output capacitor for a Buck converter based on inductor current ripple fitting. In this method, only output voltage is sampled and inductor/capacitor current ripple is fitted by use of the characteristics of output voltage ripple. ESR calculation is implemented based on the orthogonality of the voltage ripple and the fitted current ripple, which has high-precision and anti-noise characteristics. Compared to existing methods, the proposed scheme does not require additional current sensors or high-precision trigger sampling devices, making it a cost-effective solution. Based on the proposed scheme, accurate ESR estimation is achieved for both continuous conduction mode (CCM) and discontinuous conduction mode (DCM). An experimental ESR monitoring system platform is built and experimental estimation results are provided to verify the effectiveness and the precision. Full article

In industries dealing with motor drive systems, the use of real-time simulators for validating control codes is becoming increasingly mandatory. This is particularly essential for systems with advanced control codes or complex microcontroller unit (MCU) register configurations, as this validation process helps prevent accidents and shorten development time. This study presents a validation process using a real-time simulator for the beatless control of six-step operation. Six-step operation, when applied to high-speed drives, has a limitation on the number of samples per electrical rotation, which causes voltage errors. A representative of these voltage error phenomena is the beat phenomenon, resulting in torque ripple at the first harmonic and high current ripple. To mitigate this beat phenomenon, a synchronous PWM method is sometimes used. However, in practical industrial systems, it may not be feasible to synchronously adjust the inverter’s switching frequency with the rotation speed. This study proposes a beatless control method to eliminate the voltage errors caused by the beat phenomenon during six-step operation at a fixed switching frequency. The specific implementation of this control method is explained based on MCU timer register settings. While previous studies have only proposed beatless control methods, this paper goes further by implementing the proposed beatless method using the MCU (TMS320F28335) to generate gating signals and validating the implementation through simulation on a permanent magnet synchronous motor using a real-time simulator (Typhoon HIL). Full article

This work presents a fractional order Proportional Integral and Derivative controller with adaptation characteristics in the control parameters depending on the required output, gain scheduling fractional order PID (GS-FO-PID). The fractional order PID is applied to the voltage control of a DC–DC buck quadratic converter (QBC). The DC–DC buck quadratic converter is designed to operate at 12 V, although in the simulation tests, the output voltage ranges from 5 to 36 V. The performance of the GS-FO-PID is compared with the one from a classic PID. The GS-FO-PID presents better performance when the reference voltage is changed. In the same way, the behavior of the converter with the reference fixed to 12 V output is analyzed with load changes; for this case, the amplitude value of the ripple when the converter is driven by the GS-FO-PID almost has no variation. Full article

The novel concept of reliable voltage balancing on N fast high-voltage (HV) transistors, connected in series, is verified by computer modeling/experimental testing. The essence of the concept is to transfer the balancing function from conventional snubbers, resistive dividers, varistors, etc., or sophisticated gate-side control techniques, to “individual” resistive loads (of transistors) connected to “individual” HV sources of power. The concept has been implemented in the recently patented architecture of HV rectangular pulse generators. The operation of any series-connected stack requires (1) synchronization of control actions on gates of all N transistors; (2) static HV balancing on all transistors in OFF states; and (3) dynamic HV balancing during ON↔OFF transients. The goals of the new design are to achieve an exceptionally high level of HV balancing in modes (2) and (3), as well as to simplify the process of configuring/customizing the circuit. Testing confirms that new generators exhibit minimal ripple during ON→OFF transients. Reliable operation with high-quality rectangular pulses is ensured even at a voltage slew rate of more than 100 kV/µs, while each transistor blocks a voltage close to the maximum value specified in its datasheet. The presented novelties are likely suitable for high-speed instrumentation. Full article

In modern marine vessels equipped with electric propulsion systems, rectifiers are commonly used as part of the setup. However, the conventional deadbeat predictive direct power control strategy for three-phase voltage source pulse-width modulation (PWM) rectifiers tends to underperform when subjected to load variations and external disturbances. To address these limitations, this paper proposes an enhanced linear active disturbance rejection control (LADRC), incorporating virtual capacitance and an improved equivalent input disturbance strategy. The integration of virtual capacitance in the LADRC is specifically applied during load transitions. Virtual capacitance is a capacitor element simulated through the control strategy. It enhances voltage stability and dynamic response capability by compensating for voltage fluctuations and power deficits in the system. By providing a virtual active power, this approach substantially improves power tracking performance, reducing the DC voltage drop and settling time by 60% and 74%, respectively. In addition, the proposed strategy is easy to implement and does not add complexity to the LADRC. Moreover, the equivalent input disturbance is refined through virtual capacitance, enabling accurate disturbance estimation. As a result, the active power ripple and current total harmonic distortion under disturbances are reduced by 44% and 40%, respectively. The stability of the proposed strategy is comprehensively analyzed, and experimental results from a prototype system validate its effectiveness and accuracy. Full article

In this article, we propose, for the first time, to apply the flux-switching permanent magnet (OR-FSPM) generator to the oscillating water column wave energy conversion (OWC-WEC), and a novel dual three-phase 24-slot/46-pole OR-FSPM generator for OWC-WEC is designed and analyzed. The feasible phase-shift angle (PH-Angle) between the two sets of windings, namely 0°, 30° and 60°, is analyzed. The electromagnetic performance of the generator under three winding configurations is investigated, including PM flux linkage, back electromotive force (EMF), open-circuit rectified voltage, inductance, cogging torque, electromagnetic torque and unbalanced magnetic force (UMF). The prototype is manufactured, and the experimental results are consistent with that of the finite-element analysis (FEA) results. The generator with 0° and 60° PH-Angle winding configuration has stronger fault tolerance. When the 30° PH-Angle winding configuration is adopted, it has the maximum back-EMF fundamental amplitude, maximum average electromagnetic torque and the minimum torque ripple, and there is no UMF when a single set of windings is running. Therefore, the proposed novel OR-FSPM generator with 30° PH-Angle winding configuration is more suitable for OWC-WEC. Full article

This paper aims to demonstrate the energy efficiency improvements in a boost converter using supercapacitors and the Perturb and Observe (PO) control method, particularly in the context of photovoltaic (PV) systems under partial shading conditions. Supercapacitors, known for their high energy density and rapid charge/discharge capabilities, are integrated into the boost converter circuit to mitigate voltage fluctuations and enhance energy storage efficiency. The PO control method is utilized to dynamically adjust the duty cycle of the MOSFET, ensuring the output voltage remains stable at the desired level of 70 V, with an input voltage range of 30 V to 60 V. This study employs simulation techniques to evaluate performance improvements, focusing on energy efficiency and system stability when supercapacitors are used as filtering elements alongside advanced control strategies in PV systems experiencing partial shading. Simulation results indicate a significant reduction in voltage ripple and enhanced overall system efficiency, achieving a stable output voltage of exactly 70 volts. Specifically, the efficiency of the boost converter without a supercapacitor and Zener diode is 8.36%, while the configuration with a supercapacitor and Zener diode achieves 16.09% efficiency. Most notably, the configuration with a supercapacitor and without a Zener diode achieves an efficiency of 50.29%. The findings conclude that integrating supercapacitors and the PO control method in boost converters for PV applications substantially enhances energy efficiency and system stability, even under partial shading conditions. Full article

This paper aims to design the modulation strategy of SiC motor controller for vehicles with low EMI, low device loss and low voltage/current ripple. The equivalent evaluation model of input voltage, output current and switching loss of the inverter under periodic spread spectrum modulation strategy is constructed, and the quantitative relationship between each parameter of spread spectrum modulation and the three indicators is established. The input/output performance and loss level of the inverter under different spread spectrum modulation strategies are evaluated. On this basis, based on the carrier frequency distribution characteristics of periodic signal spread spectrum modulation, a “secondary frequency modulation” strategy is proposed to reduce the inverter-conducted EMI to a greater extent under the limited spread spectrum range. Experimental results show that compared with the single periodic signal spread spectrum modulation, the “secondary frequency modulation” strategy can reduce the peak value of inverter-conducted EMI to a greater extent without increasing the ripple and loss of the inverter. Full article

This paper proposes an E-core outer-rotor hybrid-excitation flux switching (OR-HEFS) machine for in-wheel direct driving application. According to the general air gap field modulation theory, the magneto-motive force (MMF) permeance model was established to investigate the air gap flux density, and then the torque generation, the flux regulation principle, and the excitation-winding-induced voltage of the E-core OR-HEFS machine were analyzed. To characterize the output performances, the influence of the design parameters was investigated for the E-core OR-HEFS machine, including the split ratio, stator tooth arc, PM arc, fault-tolerant tooth arc, rotor tooth arc, stator yoke width and rotor yoke width. The performances contained the output torque, torque ripple, flux regulation ratio, and the excitation-winding-induced voltage. On this basis, the aforementioned four performances were optimized by means of the non-dominated sorting genetic algorithm II (NSGA-II). Based on the optimization result, a prototype was manufactured and tested to verify the whole investigation of this paper. Full article

Variable Flux Reluctance Machines (VFRMs) face multiple interconnected challenges that limit their performance, particularly in high-performance applications such as electric vehicles (EVs), where smooth torque output and robust operation are critical. Chief among these challenges are complex inter-axis couplings, including cross-coupling in the dq-axis, differential term coupling in the d0-axis, and disturbances propagating from the 0-axis to the q-axis. Additionally, harmonic disturbances associated with torque ripple exacerbate performance issues, resulting in degraded dynamic behavior. These challenges hinder current loop controllers, preventing effective management of winding impedance voltage drops and inter-axis coupling terms without advanced decoupling strategies. To address these challenges, this paper proposes a novel integrated torque harmonic extended state observer (ITHESO) within a decoupled current control designed to ensure fast and accurate current tracking, system stability, and torque ripple reduction. The ITHESO identifies and compensates for total current disturbances, including harmonic components, through feed-forward compensation within the current loop. Furthermore, the influence of control parameters and the effects of parameter mismatches on stability, torque ripple reduction, and disturbance rejection are thoroughly analyzed. Experimental validations demonstrate that the proposed strategy significantly enhances torque dynamics and reduces torque ripple, outperforming the conventional Active Disturbance Rejection Control (ADRC), which does not explicitly address disturbances associated with torque ripple. These advancements position the VFRM with the ITHESO as a competitive option for high-performance EV propulsion systems, offering smooth operation, noise reduction, and reliable performance under varying speeds and loads. Full article

This paper presents a carrier waves phase shifting method to reduce the dc-link capacitor current for a dual three-phase permanent magnet synchronous motor drive system. Dc-link capacitors absorb the ripple current generated at the input due to the harmonics of the pulse width modulation (PWM). The size, cost, reliability, and lifetime of the dc-link capacitor are negatively affected by this ripple current flowing through it. The proposed method is especially appropriate for common dc-link capacitors for a dual inverter system driving two PMSMs. In this paper, the input current of each inverter is analyzed using Double Fourier Analysis, and the harmonic components of the dc-link capacitor current are determined. The carrier wave phase shifting method is proposed to reduce the magnitude of the harmonics and thus reduce the dc-link capacitor current. Furthermore, the optimum angle between the carrier waves for the maximum reduction in the dc-link capacitor current is analyzed and simulated for different scenarios considering the speed and load torque of the PMSMs. The proposed method is verified through experiments and PMSMs are driven by three-phase voltage source inverters (VSIs) modulated with Space Vector Pulse Width Modulation (SVPWM), which is the most common PWM strategy. The proposed method reduces the dc-link capacitor current by 60%, thereby significantly decreasing the required dc-link capacitance, the volume of the drive system, and its cost. Full article

In this paper, the performance of a Dual-Stator Winding Synchronous Reluctance Generator (SynRG) suitability for off-grid wind power generation is analyzed. The rotor of the SynRG has a slitted-rotor core to improve selected vital performance parameters. The SynRG with a slitted-rotor core was modeled using a two-dimensional (2D) Finite Element Method (FEM) to study the electromagnetic performance of key parameters of interest. To validate the FEA results, a prototype of the SynRG with a slitted rotor was tested in the laboratory for no-load operation and load operation for unity, lagging, and leading power factors. To evaluate the capability of the SynRG with a slitted-rotor core to operate in a wind turbine environment, the machine was modeled and simulated in Matlab/Simulink (R2023a) for dynamic responses. The FEA results reveal that the SynRG with a slitted-rotor core, compared with the conventional SynRG with the same ratings and specifications, reduces the torque ripple by 24.51%, 29.72%, and 13.13% when feeding 8 A to a load with unity, lagging, and leading power factors, respectively. The FEA results also show that the induced voltage on no-load of the SynRG with a slitted-rotor core, compared with the conventional SynRG of the same ratings and specifications, increases by 10.77% when the auxiliary winding is fed by a capacitive excitation current of 6 A. Furthermore, the same results show that with a fixed excitation capacitive current of 6 A, the effect of armature reaction of the SynRG with a slitted-rotor core is demagnetizing when operating with load currents having a lagging power factor, and magnetizing when operating with load currents having unity and leading power factors. The same patterns have been observed in the experimental results for different excitation capacitance values. The Matlab/Simulink results show that the SynRG with a slitted-rotor core has a quicker dynamic response than the conventional SynRG. However, a well-designed pitch-control mechanism for the wind turbine is necessary to account for changes in wind speeds. Full article