Proportional-resonant controller design for quasi-Z-source inverters with LC filters

One of the disadvantages of the charging systems and voltage regulation systems in alternative energy systems is that when the direct current (DC)/alternative current (AC) or AC/DC conversion is made from the energy source, the energy flow at 2ω frequency between the direct current side and the alternative current side causes ripples in the DC, inductors, and capacitors. The ripples that occur in 2ω frequency increase the harmonic distortion and reduce the efficiency in the photovoltaic energy system. For addressing this problem, different control methods are evaluated in this paper for the elimination of ripples that occur at 2ω frequency, both on the perspective of DC control side and AC control side with a thorough comparative analysis with existing results in the literature. In the present study, the model of Single-Phase Quasi-Z Source (QZS) inverter and closed-loop control methods of the inverter are examined and compared with pulse width modulation (PWM) methods. In addition, the control methods are used to eliminate the ripples at 2ω frequency in the use of inverters, and the advantages and disadvantages of these methods are presented. INDEX TERMS QZS inverter, suppression of 2ω ripple, control methods, pulse width modulation. I. INTRODUCTION

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“…In addition, high system stability level and rapid dynamic system response were also achieved. The harmonic level was found to be 1.15% [47].…”

Section: Qzs Inverter Topologymentioning

confidence: 95%

A Review of Control Methods on Suppression of 2ω Ripple for Single-Phase Quasi-Z-Source Inverter

2020

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“…Nevertheless, D(s) has the amplification effects on the input reference signal noise. Although the effects have been discussed in [18] and most of them can be ignored, together with D(s), the noise amplification effects can't be completely ignored. In addition, owing to multiple PI controllers and D(s) connected into the control layer, the superior robustness cannot be obtained.…”

Section: A Design Of Inverter Control Layermentioning

confidence: 99%

Design of a Novel Hybrid Control Strategy for ES Grid-Connected Inverter for Smooth Microgrid Transition Operation

Zheng

Lin

Lin³

et al. 2019

IEEE Access

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A novel hybrid control strategy for energy storage (ES) is applied in accordance to the recommendations by the IEEE Std. 1676. The strategy mainly consists of the model predictive controller (MPC), two-degree of freedom algorithm and modified droop control. In inverter control layer, MPC and two-degree of freedom algorithm are adopted to construct a generalized controller to enable ES operate in microgrid grid-connected and islanded operation modes with a single control structure, motivating the smooth transition between microgrid operating modes. And MPC and two-degree of freedom algorithm are used in the control layer's current inner loop and voltage outer loop, respectively. Comparing with the traditional double loop control from the perspective of structure, with the novel strategy the control layer's current inner loop is without pulse width modulation (PWM) and only a single proportional-integral (PI) controller is applied in its voltage outer loop, so that ES's robust performance can be enhanced. And because of the high frequency inverter's equivalent transfer function with the smaller time constant, MPC's transfer function approximated as being unitary. Therefore, when the two-degree of freedom algorithm construct the inverse model for the controlled object in control layer's voltage outer loop, from the application layer perspective, the control layer can be recognized as unity gain. Thus, the control layer's harmful disturbances associated with the operation mode transitions can be removed. In the application layer, through adding decoupling inductance and introducing microgrid's voltage and angular frequency feedforward compensations to carry out PQ and modified droop controls, the grid-connected and island control targets of ES application layer can be realized. In particular, when microgrid operation mode is switched to island, with the help of modified droop control, microgrid's voltage and frequency can be quickly restored to standard values. Through the theoretical derivation and simulation results, it can be proved that under microgrid's plan or non-plan operation mode switching, the proposed method can not only can not only implement the microgrid smooth switching, but also strengthen its transient performance. INDEX TERMS Model predictive controllers, two-degree of freedom, smooth transition, decoupling inductance, feedforward compensation.

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“…However, it is vulnerable to parameter changes [17,18]. During the tracking of the AC signals at a given resonant frequency of the signal control, the using of a PR controller gives a chance to remove steady-state errors [19,20].…”

Section: Introductionmentioning

confidence: 99%

A hybrid control strategy for Z-source inverter DG systems

Girgin

Sarul

2019

Automatika

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A hybrid control system for Z-source inverter (ZSI) with LC filter which is used in distributed generation (DG) systems is presented in this study. The proposed system has two different controllers, dc-side and ac-side. While designing the ac-side controller, a proportional-resonant (PR) controller was used. Besides, to be able to adjust the voltage of the Z-source capacitor according to the reference value of it, a proportional-integral (PI) controller was employed on the dc-side of the ZSI. In the end, a dynamic ZSI model was obtained by the help of small signal analysis and state space averaging. After the mathematical model of the ZSI was derived, the dc-side and acside controllers were designed. Using both controllers, inverter reference tracking performance was enhanced. The proposed controller offers superior output voltage regulation regardless of the linear and nonlinear loads. Taking into account the abrupt variations in both the dc source and linear/nonlinear load level, the effectiveness of the proposed control system was tested and supported by Matlab ® /Simulink simulations.

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Proportional-resonant controller design for quasi-Z-source inverters with LC filters

Cited by 18 publications

References 15 publications

A Review of Control Methods on Suppression of 2ω Ripple for Single-Phase Quasi-Z-Source Inverter

A Review of Control Methods on Suppression of 2ω Ripple for Single-Phase Quasi-Z-Source Inverter

Design of a Novel Hybrid Control Strategy for ES Grid-Connected Inverter for Smooth Microgrid Transition Operation

A hybrid control strategy for Z-source inverter DG systems

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