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This paper presents different state feedback approaches of finite control set model predictive control (FCS-MPC) applied to a grid-connected voltage-source converter (VSC) with an LCL filter. Besides converter-side current feedback, two multivariable control approaches and line-side current control are introduced and compared based on theoretical and experimental evaluation. As the LCL filter introduces an additional resonance frequency to the system, the use of different active damping (AD) methods in combination with FCS-MPC is discussed. Furthermore, practical control implementation issues are discussed. The presented methods reveal the great potential, high dynamic performance, and flexibility of FCS-MPC, enabling multivariable control as well as both reduced switching losses and low harmonic current distortion at the same time. Eventually, the feasibility of the theoretical control concepts is shown in a laboratory environment. [ABSTRACT FROM AUTHOR]

Passive damping is the most adopted method to guarantee the stability of LCL-filter-based grid converters. The method is simple and, if the switching and sampling frequencies are sufficiently high, the damping losses are negligible. This letter proposes the tuning of different passive damping methods and an analytical estimation of the damping losses allowing the choice of the minimum resistor value resulting in a stable current control and not compromising the LCL-filter effectiveness. Stability, including variations in the grid inductance, is studied through root locus analysis in the z-plane. The analysis is validated both with simulation and with experiments. [ABSTRACT FROM AUTHOR]

Three different control methods for the speed control of drive systems with elastically coupled loads are presented and compared. In drive applications where the load is connected to the driving motor with a drive shaft that has a finite stiffness, unwanted mechanical dynamics can occur. These unwanted dynamics can stress both the mechanical and electrical drive components. Furthermore, the shaft torsion, if neglected in the control synthesis, can dramatically reduce the achievable control performance. To overcome these challenges, the design, analysis, and comparative study of three speed control methods for a drive system with resonant loads are carried out. The considered control methods are the following: a conventional proportional-integral (PI) control, a PI-based state space control, and a model-based predictive control. To ensure a suitable basis for their comparison, the three different speed control methods are designed with equal bandwidths and are verified with the same test setup. Furthermore, all speed control methods presented use only the drive-side speed measurement to control the drive speed. [ABSTRACT FROM PUBLISHER]

Pulsewidth modulation (PWM) voltage source converters are becoming a popular interface to the power grid for many applications. Hence, issues related to the reduction of PWM harmonics injection in the power grid are becoming more relevant. The use of high-order filters like LCL filters is a standard solution to provide the proper attenuation of PWM carrier and sideband voltage harmonics. However, those grid filters introduce potentially unstable dynamics that should be properly damped either passively or actively. The second solution suffers from control and system complexity (a high number of sensors and a high-order controller), even if it is more attractive due to the absence of losses in the damping resistors and due to its flexibility. An interesting and straightforward active damping solution consists in plugging in, in cascade to the main controller, a filter that should damp the unstable dynamics. No more sensors are needed, but there are open issues such as preserving the bandwidth, robustness, and limited complexity. This paper provides a systematic approach to the design of filter-based active damping methods. The tuning procedures, performance, robustness, and limitations of the different solutions are discussed with theoretical analysis, selected simulation, and experimental results. [ABSTRACT FROM PUBLISHER]