Due to the asymmetry of load, the ageing of transmission line, the asymmetry of power grid voltage and so on, grid-connected converter often appears grid voltage unbalance at the point of common coupling. Especially f...
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Due to the asymmetry of load, the ageing of transmission line, the asymmetry of power grid voltage and so on, grid-connected converter often appears grid voltage unbalance at the point of common coupling. Especially for some high-power grid-connected converter device, if the unbalanced conditions is ignored, it will produce non-characteristic harmonics, three-phase grid current unbalance and so on that will affect the stable operation of grid-connected converter, even ruin it. Therefore, it is necessary to study the control of grid-connected converter under unbalanced grid voltage. In view of the advantages of modelpredictivecontrol in high-power converter, the control of grid-connected converter under unbalanced grid voltage based on finite control set model predictive control is studied. The goal is to control the three-phase grid current balance and enhance the stability operation of the grid-connected converter under unbalanced grid voltage. The grid-connected converter is modelled in two-phase stationary ( αβ ) coordinate system, and the modelpredictivecontrol of grid-connected converter is deduced under unbalanced grid voltage. Based on the theoretical analysis, the simulation results show the effectiveness of the proposed control strategy.
The classic modelpredictivecontrol leads to a variable switching frequency which could produce resonances in the input filter of the matrix converter, affecting the performance of the system. This paper proposes two...
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ISBN:
(纸本)9781509064267;9781509064250
The classic modelpredictivecontrol leads to a variable switching frequency which could produce resonances in the input filter of the matrix converter, affecting the performance of the system. This paper proposes two methods to mitigate the resonance of the input filter in order to solve this issue. The first method consists in a hybrid combination of modelpredictive current control with instantaneous reactive power minimization and an active damping method which consists in to emulate a virtual resistor in parallel to the input filter's capacitor. The second method imposes a sinusoidal source current instance to minimize the instantaneous reactive power at the input side. Both methods can be further enhanced with fixed switching frequency operation. Simulated results confirm the feasibility of the proposal demonstrating that the performance of the system is improved with source and load currents showing a significant reduction in the harmonic distortion produced by the filter resonance.
controlling both input and output sides of the direct matrix converter using predictivecontrol implies high computational cost due to the fact that it has twenty-seven available switching states and the needed of wei...
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ISBN:
(纸本)9781509064267;9781509064250
controlling both input and output sides of the direct matrix converter using predictivecontrol implies high computational cost due to the fact that it has twenty-seven available switching states and the needed of weighting factors. In this paper, an indirect modelpredictive current control strategy is proposed in order to simplify the computational cost while avoiding the use of weighting factors. The method is based on the fictitious dc-link concept, which has been used in the past for the classical modulation and control techniques of the direct matrix converter. Simulated results confirm the feasibility of the proposal proving that it is an feasible alternative to classical predictivecontrol strategies in this converter.
finite control set model predictive control (FCS-MPC) has been proven to be a powerful control strategy in power electronics with very high dynamic performance compared to carrier-based pulse width modulation (PWM) ap...
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ISBN:
(纸本)9781538605073
finite control set model predictive control (FCS-MPC) has been proven to be a powerful control strategy in power electronics with very high dynamic performance compared to carrier-based pulse width modulation (PWM) approaches while avoiding unnecessarily high switching frequencies that would increase switching losses. However, the limited time resolution often leads to poor steady-state performance and can only be overcome by increasing the sampling rate, which would involve an infeasibly high computational demand. This paper presents a predictive pulse pattern control (PPPC) strategy for a synchronous multiphase buck converter (SMPB) that achieves both objectives yielding in high performance for transient and steady-state operating conditions with a feasible computational demand. At every time step, a pulse pattern with minimal switching effort is selected whose switching instants are obtained by minimizing an objective function yielding in high tracking accuracy. Simulation results demonstrate the potential of the proposed control strategy to outperform state-of-the art control approaches.
The direct matrix converter has twenty-seven available switching states. This implies that the implementation of predictivecontrol techniques in this converter requires high computational cost while an adequate selec...
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ISBN:
(纸本)9781509023646
The direct matrix converter has twenty-seven available switching states. This implies that the implementation of predictivecontrol techniques in this converter requires high computational cost while an adequate selection of weighting factors in order to control both input and output sides. In addition, the technique presents a variable switching frequency which could produce resonances in the input filter damaging the performance of the system. In this paper, two indirect modelpredictive current control strategies are proposed in order to simplify the computational cost while avoiding the use of weighting factors. The first method consists in a predictive current control strategy with minimization of the reactive power minimization enhanced with an active clamping implementation which allows mitigate resonances in the input side. The second proposal consist in an indirect modelpredictive current control with imposed sinusoidal source currents in the input side. Simulated results confirm the feasibility of the proposals demonstrating that with both alternatives it is possible to mitigate the resonances on the input filter.
The following paper presents a novel indirect modelpredictivecontrol strategy for a direct matrix converter (DMC). The direct matrix converter has a large number of available switching states and therefore the imple...
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ISBN:
(纸本)9781538605073
The following paper presents a novel indirect modelpredictivecontrol strategy for a direct matrix converter (DMC). The direct matrix converter has a large number of available switching states and therefore the implementation of predictivecontrol techniques require high computational resources. In addition, the simultaneous selection of weighting factors for the control of input and output variables of the converter complicates the system tuning. In this paper, two indirect modelpredictivecontrol strategies are proposed in order to reduce the computational cost and by doing so avoid the use of weighting factors. The proposal is enhanced with a fixed switching frequency strategy in order to improve the performance of the full system. Results confirm the feasibility of the proposal by demonstrating that it is an alternative to classical predictivecontrol strategies for the direct matrix converter.
In this paper a simple indirect modelpredictive current control strategy is proposed for the control of both input and output currents in a direct matrix converter. This simplified strategy reduces the computational ...
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ISBN:
(纸本)9781509064267;9781509064250
In this paper a simple indirect modelpredictive current control strategy is proposed for the control of both input and output currents in a direct matrix converter. This simplified strategy reduces the computational cost while avoiding the use of weighting factors. The method is based on the fictitious dc-link concept, which has been used in the past for the classical modulation and control techniques of this converter. The proposal is enhanced with a fixed switching predictive strategy in order to improve the performance of the full system. Simulated results confirm the feasibility of the proposal demonstrating that it is an alternative to classical predictivecontrol strategies.
In this paper an indirect modelpredictive current control strategy is proposed. The proposed method simplifies the computational cost while avoiding the use of weighting factors. Weighting factors are an issue for mo...
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ISBN:
(纸本)9781538631232
In this paper an indirect modelpredictive current control strategy is proposed. The proposed method simplifies the computational cost while avoiding the use of weighting factors. Weighting factors are an issue for modelpredictivecontrol in a direct matrix converter due to the large number of available switching states and necessity to control both input and output sides of the converter.
The classic modelpredictivecontrol presents a variable switching frequency which could produce resonances in the input filter of the matrix converter, affecting the performance of the system. In this paper a model p...
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ISBN:
(纸本)9781538631232
The classic modelpredictivecontrol presents a variable switching frequency which could produce resonances in the input filter of the matrix converter, affecting the performance of the system. In this paper a modelpredictivecontrol strategy is proposed with fixed switching frequency operation which is enhanced with an active damping method in order to mitigate resonances of the input filter. The operation at fixed switching frequency is accomplished by emulating space vector modulation using predictivecontrol and the active damping method consists in emulating a virtual resistor in parallel to the filter's capacitor. Simulated results confirm the feasibility of the proposal demonstrating that the performance of the system is improved ensuring sinusoidal source and load currents with a reduction of the harmonic distortion produced by the filter resonance.
The classic modelpredictivecontrol presents a variable switching frequency which could produce high ripple in the controlled waveforms or resonances in the input filter of the matrix converter, affecting the perform...
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ISBN:
(纸本)9781538631232
The classic modelpredictivecontrol presents a variable switching frequency which could produce high ripple in the controlled waveforms or resonances in the input filter of the matrix converter, affecting the performance of the system. This paper presents two modelpredictivecontrol strategies with fixed switching frequency operation which allow a better performance of the system. The operation at fixed switching frequency is accomplished by emulating space vector modulation using predictivecontrol. Simulated results confirm the feasibility of the proposal demonstrating that the performance of the system is improved ensuring sinusoidal source and load currents with a reduced harmonic distortion of the controlled variables.
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