Search Results (25)

This paper simplifies indirect resonant switched-capacitor (ReSC) converters using the state-space average model method. The operation principles of the 4:1 and 5:1 ReSC converters derived from the Dickson (4:1) circuit are analyzed, and the corresponding state-space average matrices are derived based on their equivalent circuits. The resonant inductor of the specific resonant branch is eliminated by analyzing the composition of the state-variable matrix, thereby obtaining the simplified topologies of 4:1 and 5:1 indirect ReSC converters. The simplified topologies are simulated and experimentally verified. The results prove the correctness of the state-space average modeling method and the effectiveness of the simplified topologies. Full article

Focused on addressing harmonic suppression in multiphase indirect matrix converters (IMCs), this study explores spread-spectrum modulation technology through ripple analysis calculations. We introduce a current ripple spread-spectrum modulation (CR-SSM) method tailored for multiphase IMC systems. In this approach, a 3 × 6-phase IMC is modeled as a two-port network, and a small-signal model of the output side is established. The transfer function is utilized to analyze the two-port network in the complex frequency domain (s-plane). The time-domain expression of the output current ripple is derived in vector form. Subsequently, the distribution of the output ripple and locus are determined based on specified constraints. The carrier frequency is dynamically adjusted online according to the specified ripple locus. Compared to classical periodic PWM methods, this approach offers a broader range of frequency variations and achieves a more uniform output spectrum. Furthermore, CR-SSM optimizes system efficiency and enhances spread-spectrum modulation. Experimental results demonstrate that this method effectively enhances the quality of input and output waveforms in multiphase IMC systems. Full article

A matrix-integrated single-stage isolated MF/HF AC-AC/DC-AC/AC-DC converter topology stands out as an innovative concept, offering a multitude of advantages including minimal output current THDs, near UPF, 4Q operation, smooth BPF capability, and increased power density leading to the converter’s enhanced efficiency, cost-effectiveness, and reliability. These characteristics render it an exemplary choice for RE-based power conversion applications. In fact, the matrix-integrated single-stage isolated MF/HF converters have witnessed an increased adoption of RE-based grid interconnection in recent years, specifically within solar PV, WECS, grid-tied offshore WF, and FC-based applications. RE sources produce variable and intermittent AC power by nature, further necessitating conversion to a stable and grid-compatible AC voltage and frequency. This is where MCs offer distinct advantages when contrasted with the conventional indirect dual-stage VSC-based rectifier–inverter topology. In this paper, a total of 22 matrix-integrated HF isolated converter topologies are broadly explored. Our study provides a comprehensive analysis and classification of matrix-integrated isolated single-stage MF/HF AC-AC converters, DC-AC inverters, and AC-DC rectifier topologies including modified topology architectures, control method, modulation techniques along with significant applications. Within this scope, the matrix-integrated converter topologies are categorized based on their architectures and other relevant subvariants. Our primary objective of this study is to impart a clear understanding of the overarching framework and principles of the matrix-integrated single-stage isolated MF/HF converter topologies and stimulate the creation of new topologies that cater to specific requirements for grid-interconnected systems. Full article

In the process of hardware-in-the-loop simulations (HILs) of indirect matrix converters (IMCs), solving the mathematical models of complex multiswitching converter topologies has become a major problem. The conventional approach is to split the complex mathematical model into multiple serial subsystems; however, this inevitably produces delays in the simulation steps between different subsystems, leading to numerical oscillations. In this paper, the method of latency-free decoupling is adopted, which has no time-step delay between different subsystems, making each subsystem a parallel operation. This can improve the numerical stability of the simulations and can effectively reduce the step size of the real-time simulation and alleviate the problem of real-time simulation resource consumption. In this paper, we discuss in detail the modeling process of IMC hardware-in-the-loop simulations with Finite Control Set Model Predictive Control (FCS-MPC), and experimentally validate our method using the Speedgoat test platform, resulting in a simulation step size of less than 200 ns. The simulation results are compared with the results of Matlab’s Simpower power system, which allows us to evaluate the accuracy of our model. Full article

The popularity of multiphase drives is increasing due to the growing interest in drives with more than three phases. One promising topology is the multiphase matrix converters, which enable the implementation of a single-stage AC/AC power conversion system with bidirectional power flow capability. In this paper, we present the implementation of indirect control for a practical sample of the direct matrix converter. To reduce the overall cost of the control solution for these types of converters, we utilized low-cost FPGA and DSP. The usage of only DSP itself was not possible due to low number of available PWM output needed for 3 × 5 MxC driving. Another reason is commutation, which must be precise and fast to avoid any hazardous states in the converter. Due to these problems, the authors decided to implement an algorithm of a combination of DSP and FPGA, where FPGA is used for time critical operations. The indirect algorithm treats the converter as two separate parts, the rectifier and the inverter, with the DC-LINK being fictitious. The matrix converter is composed of compact modules, and the entire system is verified. The practical verification demonstrates that matrix converters can produce a wide range of output frequencies and achieve input power factor control. Finally, we compare and review the practical model with the simulation model, examining efficiency and other parameters. Full article

This paper investigated and demonstrated an electric drive topology with inherently high reliability and improved performance. The topology combines a five-phase combined star-pentagon synchronous reluctance machine (SynRM) and a power electronic “matrix” converter without vulnerable electrolytic capacitors, which are often a point of failure of conventional drives. This drive is suitable for harsh environments, with possibly high ambient temperatures and limited maintenance. In this paper, an accurate model of the five-phase combined star-pentagon SynRM was introduced considering the effect of magnetic saturation and cross saturation on dq-flux-linkages. The five-phase combined star-pentagon SynRM will be connected to a three-to-five-phase indirect matrix converter (IMC) and the indirect field-oriented control based on a space vector pulse width modulation was applied. The introduced SVM commutates the bidirectional switches of the IMC at zero current which enhance and minimize the switching losses. The performance of the proposed drive system was studied and experimentally validated at different loading conditions. Finally, the reliability, cost, and performance of the proposed drive system were compared with the conventional drive system (three-phase star-connected SynRM fed from rectifier-inverter). Full article

This paper introduces and analyzes the power losses of a five-phase drive system based on an indirect matrix converter (IMC) and a five-phase synchronous reluctance motor (SynRM). The different loss components in the power converter and the motor have been discussed and analyzed. Moreover, a control strategy is applied to decrease the power converter losses and make the system superior to the conventional one. The carrier-based pulse-width-modulation (CBPWM) method is used for this. Through the CBPWM, switching losses are kept as low as possible in this technique by ensuring that the rectifier stage experiences zero current commutation. To achieve this, the rectifier and inverter stages are synchronized so that the commutation in the rectifier stage occurs at the zero vectors of the inverter, which corresponds to a zero DC-link current. The converter will therefore have less switching losses thanks to the rectifier’s null value. Experimental validation has shown the usefulness of the proposed CBPWM in providing lower switching losses in the IMC. Additionally, a comparison of the proposed drive system’s performance with a traditional three-phase SynRM-based inverter will be carried out in the speed and torque control modes. Full article

Output performances including voltage error and THD effected by hexagon vector and basic vector with traditional indirect space vector overmodulation method are analyzed, and an improved overmodulation method based on input current vector synthesized is presented. Simulation and experimental results are carried out to validate the effectiveness of the proposed method. Simulation results indicate that the proposed input current vector-synthesized overmodulation strategy has better output performances. The experimental results verify that theoretical analysis is right and the proposed method is feasible. Full article

A variety of modulation strategies for suppressing output common-mode voltage (CMV) of indirect matrix converters (IMC) have been proposed, but most of them mainly reduce the peak of CMV by 42.3%. The frequency-domain characteristics of CMV have not been deeply analyzed. In order to improve the theory of frequency-domain characteristics of output common-mode voltage of IMC, this paper proposed a common-mode frequency domain analysis of five common-mode voltage peak suppression modulation methods for IMC. The common-mode voltage spectrum corresponding to the five modulation methods is obtained by the triple Fourier series, and the variation laws of the output common-mode components of the five modulation methods under different modulation indexes are compared and analyzed. By comparing and analyzing the low-frequency amplitude characteristics and high-frequency amplitude characteristics of five modulation methods, the suppression performance of the five modulation methods is evaluated. Finally, experiments verify the correctness of the theoretical analysis of the frequency domain characteristics of the output common-mode voltage of the indirect matrix converter. Full article

This article presents and analyzes a three-to-five-phase indirect matrix converter (IMC) structure for directly supplying a five-phase static $R–L$ load from a three-phase supply. The IMC topology offers a lower number of switches, a simple commutation procedure and a cost-effective clamping circuit in comparison to the direct matrix converter (DMC). A simple clamping circuit with one ultrafast diode and one small capacitor is proposed to protect the switches of the IMC from overvoltage. The issues of powering up the IMC with the simple clamping circuit is discussed in detail. The instructions for the safe start-up of the IMC with the proposed clamping circuit is introduced based on the simulated and the measured analyses. Moreover, a carrier-based pulse-width-modulation ($\mathrm{CBPWM}$) method is also presented in order to control the switches of the IMC. The presented CBPWM method creates PWM pulses for both the inverter and the rectifier legs by using only one symmetric and triangular carrier signal. Finally, experimental and simulation testing with a five-phase R–L load demonstrate the viability and the efficiency of the introduced CBPWM algorithm for the suggested IMC. Full article

This paper focuses on the application of the direct torque control based on space vector modulation (DTC-SVM), combined with the input–output feedback linearization (IOFL) technique on a three-phase dual open-end windings induction motor (DOEWIM) fed by two dual indirect matrix converters. The main aim of integrating the non-linear technique is to overcome the main drawbacks met within the application of the conventional DTC-SVM on dual-stator induction motor (DSIM), such as the torque and flux ripples reduction, the stator harmonics current minimization, and the elimination of the common-mode voltage (CMV). Furthermore, it is proved in this paper that the proposed control on DOEWIN can ensure more flexibility versus speed reverse and variation, load torque changes, and motor parameters variation. The obtained results prove the validity of the proposed control on the studied induction motor topology in ensuring the main aforementioned advantages compared to the conventional DTC-SVM control on DSIM, which presents a promising solution, especially in industrial applications in which high-power motors are required. Full article

In order to identify ecological relationships of participating countries in the transfer system of ecological capital embodied in global trade, this paper takes the international trade of China and its partners from 2002 to 2017 as a case, and uses the ecological footprint (EF) measured by the optimized product land-use matrix (PLUM) method to quantify ecological capital for the value of macro-ecological resources, then uses the ecological network analysis (ENA) method to construct a complete transfer network of trade-embodied ecological capital and uses a utility analysis to identify ecological relationships between trading countries. Our results show that: (1) Throughout the study period, competition relationships with 61% dominated in the network, and the countries that have a pair-wise competition relationship with China are mainly located in central and western Europe, northeastern Europe, North America, southern Asia and eastern Asia. (2) Indirect utility determines the dominant ecological relationship in system, and it mainly converts dominant ecological relationships from control to competition by transforming exploit into competition. (3) China is looking to creating a more mutually beneficial trading environment at the expense of its own interests. (4) A global crisis event is likely to result in the control of ecological capital in more countries, and in its aftermath, the world is likely to be in a highly competitive environment. Reducing ecological capital consumption by improving energy efficiency and optimizing the global trading environment into a trading system dominated by mutualism relationships can be effective ways for countries around the world to achieve sustainable development post-COVID-19 crisis. Full article

A continuous control set model predictive power control strategy for an indirect matrix converter is proposed in this paper. The load reactive power, the load active power, and the input reactive power are controlled simultaneously. This control strategy can obtain output waveforms with fixed switching frequency. Additionally, an optimal switching sequence is proposed to simplify the commutations of the indirect matrix converter. To suppress the input filter resonance, an active damping method is proposed. Experimental results prove that the proposed method features controllable input reactive power, controllable load active and reactive power, fixed switching frequency output waveforms, zero-current switching operations, and effectively suppresses input filter resonance. Full article

In order to expand the speed range for an indirect matrix converter–surface mounted permanent magnet synchronous motor drive (IMC-SPMSM), a wide speed range operation control strategy based on a flux-weakening control and an over-modulation method is proposed in this paper. In the stage of the inverter, an IMC over-modulation method is designed, which increases the fundamental voltage transmission ratio (VTR) to 1. In addition, considering the variation of the voltage limit boundary of the IMC with motor speed, flux-weakening control is implemented based on the voltage error feedback method, which maximizes the voltage utilization rate by setting the endpoint of the output voltage vector on the voltage boundary during the flux-weakening operation. In the stage of the rectifier, over-modulation is automatically switched on or off according to operation requirements by a modulation depth controller. Finally, experimental results show that the proposed strategy increases the maximum speed of the IMC-SPMSM by nearly 35% compared to the maximum torque per ampere (MTPA) method. Besides, the enlarged voltage margin by the rectifier stage over-modulation effectively shortens the setting time. Full article

Matrix converters (MCs) allow the implementation of single-stage AC/AC power conversion systems (PCS) with inherent bidirectional power flow capability. By avoiding the typical DC-link capacitor, MCs have the potential to achieve higher power density with a more reliable operation and less maintenance when compared with conventional two-stage AC/DC/AC PCS. For these reasons, matrix converters have been receiving significant attention from the academic sector but have not yet been implemented on a large industrial scale. This article reviews the Direct Matrix Converter (DMC) and the Indirect Matrix Converter (IMC) along with the respective actual and most important modulation methods. Simulation results are provided to validate the theoretical analysis and to get a deep insight about the implementation of space vector modulation (SVM) and respective switching pattern generator. Full article