A Voltage Modulated DPC Approach for Three-Phase PWM Rectifier

EEE Ind. Electron. Mag.

Blaabjerg

et al. 2019

Self Cite

This article discusses the mathematical relationship between the grid-voltage-modulated-directpower-control (GVM-DPC) and the vector-current-control (VCC) for three-phase voltage-source-converters (VSCs). It reveals that the GVM-DPC is equivalent to the VCC at the steady-state, yet presents a superior transient performance by removing the need of phase-locked loop (PLL). That means the GVM-DPC solves the disadvantage of conventional DPC such as poor steady-state performance. Moreover, the GVM-DPC will reduce the computational burden in comparison with the VCC due to the absence of Park transformation and PLL. Consequently, we can expect that the GVM-DPC method has a good capability of plug-and-play for the VSC. Finally, the experiment results match the theoretical expectations closely. Index Terms Direct power control, vector current control, voltage source converters, phase-locked loop. I. INTRODUCTION OF CONTROL OF GRID-CONNECTED VOLTAGE-SOURCE CONVERTERS Voltage source converter (VSC) is widely used in the application of smart grid, flexible AC transmission systems, and renewable energy sources (e.g., wind and solar) [1]-[6]. Various control methods are researched for VSC to improve its performance, stability, and robustness [7].

“…Notice that, (13) is converted into an LTI system with some coupling states. Consequently, it can be easily analyzed and designed by using conventional linear control techniques [31].…”

Section: Grid Voltage Modulated Direct Power Controlmentioning

confidence: 99%

mentioning

confidence: 99%

Control of Grid-Connected Voltage-Source Converters: The Relationship Between Direct-Power Control and Vector-Current Control

EEE Ind. Electron. Mag.

Blaabjerg

et al. 2019

Self Cite

“…Recently, Gui et al introduced a grid voltage modulated-DPC (GVM-DPC), which has a good transient response and steady-state performance [47]- [49]. The key point of the GVM-DPC is that converts the original nonlinear system into an LTI system, which also can be easily designed and analyzed by using various linear control techniques [50].…”

Section: Introductionmentioning

confidence: 99%

Vector Current Control Derived from Direct Power Control for Grid-Connected Inverters

IEEE Trans. Power Electron.

Blaabjerg

2019

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We propose a vector current control derived from direct power control (VCC-DPC) for a three-phase voltage source inverter (VSI) in the synchronous rotating frame through instantaneous real and reactive powers. The proposed VCC-DPC method has the same control structure as the conventional VCC except for the coordinate transformation, since we obtain the d-q axes currents model of VSI without using Park transformation and the PLL system. Consequently, the proposed method has the same property as the conventional VCC if the PLL extracts the phase angle of the grid voltage correctly. However, with the consideration of the slow dynamics of the PLL, the proposed method has an enhanced dynamical performance feature compared with the conventional VCC. Moreover, it has another benefit that the reduction of the computational burden could be expected since there is no Park transformation and the PLL in the controller implementation. We can guarantee that the closed-loop system with the proposed method is exponentially stable in the operating range. Finally, both simulation and experimental results using a 15-kW-inverter system match the theoretical expectations closely. Index Terms-Voltage source inverter, vector current controller, instantaneous real and reactive powers, exponentially stable.

“…concept [38], [39]. However, for the GVM-DPC method, it starts from a strong assumption that it needs a non-distorted grid voltage.…”

Section: Introductionmentioning

confidence: 99%

Voltage-Modulated Direct Power Control for a Weak Grid-Connected Voltage Source Inverters

IEEE Trans. Power Electron.

et al. 2019

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In this paper, we design a voltage modulated direct power control (VM-DPC) for a three-phase voltage source inverter (VSI) connected to a weak grid, where the PLL system may make the system unstable if the conventional vector current control (VCC) method is applied. Compared with the conventional VCC method, the main advantage of the proposed VM-DPC method is that the PLL system is eliminated. Moreover, in order to inject the rated real power to the weak grid, the VSI system should generate some certain amount of reactive power as well. An eigenvalues based analysis shows the system with the proposed method tracks its desired dynamics in the certain operating range. Both simulation and experimental results match the theoretical expectations closely. Index Terms-Voltage source inverter, voltage modulated direct power control (VM-DPC), vector current controller, weak grid, stable system.