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The maximum energy that can be harvested from a photovoltaic (PV) system at any instant depends on the effectiveness and response time of the maximum power point tracking (MPPT) algorithm used and related controllers. To facilitate proper controller design, a precise mathematical model of the system is required. This paper presents a comprehensive small signal model capable of describing the dynamics of the power stage and controllers. The power stage consists of a PV system and a dc–dc boost converter including the parasitic elements operating in inverse-buck mode. The MPPT and PV voltage controller constitute the control system. The steady state and transient responses of the system are evaluated by controller-hardware-in-the-loop approach where the power stage is simulated in a real time digital simulator and the control operations are performed in a digital signal processor. The frequency response is experimentally determined using a Gain-Phase analyzer. This unique approach allows control system designers to test and validate a control system design before implementing it with a laboratory scale hardware or any real-life application. This method adds an extra layer of design authentication on top of conventional offline simulations. [ABSTRACT FROM AUTHOR]

This paper presents the digital implementation of a boundary controller with unipolar switching characteristic for single-phase voltage source full-bridge inverters. This paper expands the application of a second-order switching surface-based control method to unipolar switching of single-phase voltage source inverters (VSIs) using a finite-state machine. The finite-state machine has been formulated considering four different states of the inverter; positive,zero1, negative, andzero2. The second-order boundary control governs the current state of the system and provides proper switching action to keep the system within the desired reference. The control law is implemented digitally in F28m35x digital control card. A full-bridge inverter topology is used to achieve the three-level voltage switching. Various simulations and experiments were performed in a 550 VA, 120 V, 60 Hz VSI with a digitally implemented controller to verify the theoretical predictions. A high-quality voltage output was obtained for various loading conditions. The transient performance of the controller was investigated using a reference and load changes. A comparison of the implementation was made with the existing classical controllers to verify the fast-dynamic response of the system. [ABSTRACT FROM AUTHOR]