EPE Association: EPE 2020 - DS2e: Grid Connected Converters

EPE 2020 - DS2e: Grid Connected Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 02: Power Converter Topologies and Design > EPE 2020 - DS2e: Grid Connected Converters

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   Control of Parallel Connected Voltage Source Inverters in a Microgrid for Experimental Testing
By Jesus David VASQUEZ PLAZA [View]
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Abstract: This article describes the primary and secondary controls of voltage source inverters that are part of a custom-made AC microgrid for testing control strategies. The conceptual and physical structure of the microgrid is described. A cascade voltage-current control and a state feedback control are implemented for inverters with LCL output filters. Also, the conventional droop controls are implemented for power sharing. Simulation and experimentation results are presented of voltage, current and load sharing controls between two inverters of the microgrid, which validate these control strategies for teaching of microgrid control strategies.

   Current Control of a Grid-Connected Single-Phase Voltage-Source Inverter with LCL Filter
By Alfonso PARREÑO TORRES [View]
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Abstract: The control in power electronic systems play an important role in the connection of renewable energy sources to the electrical grid. This paper presents the design of a current control for a grid-connected single-phase voltage source inverter (VSI). The VSI is connected to the grid through an LCL filter in order to attenuate the switching harmonics in the output signal. The proposed control provides an active damping at the resonance frequency and tracks the current reference with a fast dynamic response. The control scheme is based on a resonant regulator implemented in a structure with two nested controllers. The proposed control ensures a direct pole-placement of the closed-loop transfer function without the need for state observers and only measuring the grid current. Simulation results assess the validity of the control method.

   LCL Filter Design for Three Phase AC-DC Converters Considering Semiconductor Modules and Magnetics Components Performance
By Marco STECCA [View]
[Download]

Abstract: LCL filters are commonly adopted to attenuate the current harmonics produced by Pulsewidth-Modulation Voltage Source Converters. Due to the nature of LCL filters, several combinations of L and C can deliver the attenuation required by the standards. Then, the optimal configuration is generally evaluated also considering power density, costs and filter efficiency. This paper shows that the semiconductor efficiency should also be considered as an important design variable. It is shown that the AC ripple across the converter side inductor can reduce, until a certain extent, the overall semiconductor losses, when commercial IGBTs and the respective anti-parallel diodes are used. Reduced losses have benefits in terms of semiconductor modules lifetime, chip area, cost reduction and lessen the cooling requirements. Higher AC ripple, however, negatively affect filter losses. Nonetheless, inductive components are much less critical in terms of losses dissipation and lifetime than semiconductors.

   LQR and H-infinity Control of Voltage Source Inverters for AC Microgrids
By JORGE TENORIO [View]
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Abstract: This paper presents a voltage controller design of three-phase voltage source inverters using $LQR$-based active damping and H$\infty$ control strategy. Active damping consists of an $LQR$ voltage and current feedback of $LC$ filter in the $\alpha\beta$ frame. In addition to the damping obtained in the $LC$ filter, the proposed $LQR$ strategy allows increasing the bandwidth of the system to reject high frequency disturbances. Three-phase voltage regulation is achieved in the $\alpha\beta$ frame using the H$\infty$ control strategy. In this strategy is used a new four order sensitivity functions to obtain very low tracking error and rejection of harmonic disturbances generated by nonlinear loads. The controller has been validated in laboratory tests using 2kW-220V three-phase inverters and non-linear loads. This controller has been compared to resonant proportional control and better performance has been verified. A $THD\_v$ = $1.3\\%$ has been experimentally obtained when a nonlinear load is connected.

EPE 2020 - DS2e: Grid Connected Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 02: Power Converter Topologies and Design > EPE 2020 - DS2e: Grid Connected Converters
	[return to parent folder]

	Control of Parallel Connected Voltage Source Inverters in a Microgrid for Experimental Testing By Jesus David VASQUEZ PLAZA	[View] [Download]
Abstract: This article describes the primary and secondary controls of voltage source inverters that are part of a custom-made AC microgrid for testing control strategies. The conceptual and physical structure of the microgrid is described. A cascade voltage-current control and a state feedback control are implemented for inverters with LCL output filters. Also, the conventional droop controls are implemented for power sharing. Simulation and experimentation results are presented of voltage, current and load sharing controls between two inverters of the microgrid, which validate these control strategies for teaching of microgrid control strategies.

	Current Control of a Grid-Connected Single-Phase Voltage-Source Inverter with LCL Filter By Alfonso PARREÑO TORRES	[View] [Download]
Abstract: The control in power electronic systems play an important role in the connection of renewable energy sources to the electrical grid. This paper presents the design of a current control for a grid-connected single-phase voltage source inverter (VSI). The VSI is connected to the grid through an LCL filter in order to attenuate the switching harmonics in the output signal. The proposed control provides an active damping at the resonance frequency and tracks the current reference with a fast dynamic response. The control scheme is based on a resonant regulator implemented in a structure with two nested controllers. The proposed control ensures a direct pole-placement of the closed-loop transfer function without the need for state observers and only measuring the grid current. Simulation results assess the validity of the control method.

	LCL Filter Design for Three Phase AC-DC Converters Considering Semiconductor Modules and Magnetics Components Performance By Marco STECCA	[View] [Download]
Abstract: LCL filters are commonly adopted to attenuate the current harmonics produced by Pulsewidth-Modulation Voltage Source Converters. Due to the nature of LCL filters, several combinations of L and C can deliver the attenuation required by the standards. Then, the optimal configuration is generally evaluated also considering power density, costs and filter efficiency. This paper shows that the semiconductor efficiency should also be considered as an important design variable. It is shown that the AC ripple across the converter side inductor can reduce, until a certain extent, the overall semiconductor losses, when commercial IGBTs and the respective anti-parallel diodes are used. Reduced losses have benefits in terms of semiconductor modules lifetime, chip area, cost reduction and lessen the cooling requirements. Higher AC ripple, however, negatively affect filter losses. Nonetheless, inductive components are much less critical in terms of losses dissipation and lifetime than semiconductors.

	LQR and H-infinity Control of Voltage Source Inverters for AC Microgrids By JORGE TENORIO	[View] [Download]
Abstract: This paper presents a voltage controller design of three-phase voltage source inverters using $LQR$-based active damping and H$\infty$ control strategy. Active damping consists of an $LQR$ voltage and current feedback of $LC$ filter in the $\alpha\beta$ frame. In addition to the damping obtained in the $LC$ filter, the proposed $LQR$ strategy allows increasing the bandwidth of the system to reject high frequency disturbances. Three-phase voltage regulation is achieved in the $\alpha\beta$ frame using the H$\infty$ control strategy. In this strategy is used a new four order sensitivity functions to obtain very low tracking error and rejection of harmonic disturbances generated by nonlinear loads. The controller has been validated in laboratory tests using 2kW-220V three-phase inverters and non-linear loads. This controller has been compared to resonant proportional control and better performance has been verified. A $THD\_v$ = $1.3\\%$ has been experimentally obtained when a nonlinear load is connected.