Improved Operation Strategy with Alternative Control Targets for Voltage Source Converter under Harmonically Distorted Grid Considering Inter-Harmonics

Abstract

This paper proposed an improved control method for grid-connected voltage source converter (VSC), when the grid voltage consisted of the integer harmonics and inter-harmonics. Control object of the proposed control can be alternated to achieve the sinusoidal current or smooth output power, which enhances the operation adaption of VSC under the harmonically distorted grid. On the basis of a PI regulator in the fundamental current control loop, the novel control strategy was proposed with a supplementary controller which consisted of a prepositive high-pass filter and a modified proportional-derivative controller. In the proposed control, the inter-harmonics could be suppressed without detecting frequency, while the traditional resonator was effective in the premise of knowing the harmonics frequency. Also, the influence of control gain on the steady performance and the stability of VSC was analyzed, and the influences on the fundamental control caused by the proposed controller were also analyzed to verify the practicability of the proposed control strategy. Finally, the effectiveness of the proposed strategy was verified by the experiments.

High Frequency Resonance Damping Method for Voltage Source Converter Based on Voltage Feedforward Control

“…The implementation of the proposed voltage feedforward control for VSC system is illustrated in Figure 6. The vector control based on PI controller is employed since it guarantees that the output current i gdq can track the reference i* gdq accurately, in which the reference can be calculated by the power reference [29,30],…”

“…Besides the output of PI controller and HFR damping controller, the decoupling component E dq = -ji g ω g L lf was concluded in the voltage reference as well, which can counteract the coupling of VSC control in dq frame [29][30][31].…”

Damping control of high‐frequency resonance based on voltage feedforward for voltage source converter under a parallel compensated grid

“…However, this method introduces a non‐causal controller, which has a higher numerator order than denominator order, thus the delay components are ought to be employed to modify the HFR damping controller, which can affect the phase of damping controller and thereby affect the phase amendment performance and reduce the practicability [16, 17]. More importantly, the method introduces high‐frequency noise since the gain of the controller increases with an increasing frequency [22–24].…”

Decoupled Current Controller Based on Reduced Order Generalized Integrator for Three-Phase Grid-Connected VSCs in Distributed System

“…In recent years, distributed power generation system (DPGS) has attracted increasing attention with the aggravation of global energy shortage and environmental issues [1][2][3][4][5]. A typical DPGS is shown in Figure 1; due to the intermittence of renewable energy sources (RESs) such as PV systems and wind turbines, energy storage systems (ESSs) based on battery and supercapacitor are used to suppress power fluctuations, which improves the reliability and quality of power supply.…”

“…Proportional-resonant (PR) and vector proportional-integral (VPI) controllers are, respectively, equivalent to conventional PI and complex-vectors PI (cPI) regulators, which are implemented in a positive and negative sequence SRF simultaneously [17]. It assures perfectly tracking AC reference signals without steady-state errors for both sequences [5][6][7]9,12,14,15,18]. However, the negative-sequence term (i.e., −jω e ) of conjugated poles introduces two times control frequency fluctuation, bringing slower dynamic response and more severe cross-coupling [16,26].…”