Modified linear active disturbance rejection control for microgrid inverters: Design, analysis, and hardware implementation

Abstract

Summary Microgrid inverters are characterized by nonlinearities, strong coupling, and switching flexibility, by which traditional proportional‐integral control is inadequate to realize a satisfactory control performance due to its local linearization. This paper attempts to design a modified linear active disturbance rejection control (MLADRC) for voltage control of microgrid inverters. Under the framework of extended state observer, voltage error derivative is obtained indirectly by the measurement of filter capacitor current, such that the observation performance of extended state observer could be significantly improved. Furthermore, a first‐order inertial link is employed in the perturbation loop to effectively suppress observation noises. A thorough frequency response analysis of MLADRC, linear active disturbance rejection control, and proportional‐integral control is undertaken, which shows that MLADRC owns superior disturbance rejection performance than that of others. Lastly, hardware experiment validates the effectiveness and implementation feasibility of MLADRC.

Linear Active Disturbance Rejection Control Strategy with Known Disturbance Compensation for Voltage-Controlled Inverter

“…The Bode diagram of the transfer function Φ r (s) with different ω c has been studied in [19][20][21][22]25,26], so they are not mentioned in this paper. The Bode diagrams of the transfer function Φ d (s) and Φ n (s) are given in Figure 5, where ρ = 1 and ω c = 2000 rad/s.…”

“…In the aspect of the inverter voltage control, the first-order differential signal of the voltage reference is introduced into the original LSEF [25], and the bandwidth is effectively increased. The filter capacitor current is measured to obtain the voltage error derivative indirectly in [26], so the observation performance of ESO could be significantly improved. In other aspects, such as the active power filter [27] and solid oxide fuel cell power plant [28], the ADRC has been successfully applied.…”

Integrated Framework for Development, Emulation, and Testing of High-Level Converter Control Functions for Distributed Generation Sources

“…Furthermore, active and reactive power production and utilisation have been extensively analysed in recent years. Microgrid inverters strong coupling together with accompanying nonlinearities is discussed in [19]. The analysis of simultaneous inverter currents quality enhancement together with power oscillations minimisation during unbalanced grid faults is shown in [20], [21].…”

Analysis and Verification of Compound SRFPI-LADRC Strategy for an Off-Grid Single-Phase Inverter

“…It treats internal and external disturbances as the total disturbance and utilizes the input and output targets to estimate the disturbances for disturbance rejection [25]. In addition, as a general-purposed control structure [26], the LADRC has been widely used in control systems with step reference signals such as servo systems [27,28] and three-phase inverters in the SRF [29,30] but relatively few in single-phase inverters [31][32][33]. e main reason is that it is unable to eliminate the steady-state error when tracking a sinusoidal signal.…”