EPE Association: EPE 2020 - LS3a: Modular Multilevel Converters

EPE 2020 - LS3a: Modular Multilevel 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 - LS3a: Modular Multilevel Converters

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   Direct Multivariable Control for MMC: Digital Signal Processing and Experimental Results
By Daniel DINKEL [View]
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Abstract: Modular Multilevel Converters (MMC) have opened the road for power electronics to many new anddemanding applications in the high power range. The increased degrees of freedom of MMC and thehigher number of variables to be controlled have to be fully used by advanced multivariable control(MVC) concepts. Fast and independent control of all essential variables establishes a solid basis forfully electronic fault management, fault ride through and tight control of the internal arm energies of the converter. The new MVC concept - suitable for MMC with high level count - has been implemented based on FPGA-Hardware and digital signal processing of the measured values. Experimental results of the control performance, using a down scaled MMC with 96 submodules (SM), are presented.

   Energy-Balancing of a Modular Multilevel Converter Using an Online Trajectory Planning Algorithm
By Qiuye GUI [View]
[Download]

Abstract: Modular Multilevel Converter (MMC) energy balancing is a nontrivial open-loop control problem, since the choice of a technically meaningful output leads to an internal dynamics. The method used in this paper relies on an MMC arm energy model, which allows algebraic parametrization of almost all system variables and the rest can be obtained by integration of a small subsystem of low order. The solution introduced in this paper is to plan appropriate trajectories for all variables such that the balancing goal is met. The planned trajectories are given to the control system, which leads to a feedforward balancing effort supporting the standard feedback balancing control. In contrast to the previous approach, an analytical solution was obtained providing for efficient real-time trajectory planning. Test bench measurements confirm improved energy control performance compared to standard feedback balancing.

   Reducing the Energy Storage Requirements of Modular Multilevel Converters with Optimal Capacitor Voltage Trajectory Shaping
By Simon FUCHS [View]
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Abstract: The required module capacitance value is a driving factor of the volume and cost of modular multilevel converters (MMC). In order to minimize the required capacitance value, an optimal circulating current and common mode (CM) voltage injection strategy which keeps the conduction losses and die CM voltage as low as possible is proposed in this paper. Unlike previous methods from literature that only focus on minimizing the amplitude of energy fluctuation in the arm capacitors, the proposed optimization procedure is based on the optimal shaping of both the arm voltages and energies. As a result, the proposed optimization scheme achieves a further reduction in the required capacitance value of up to 42\% compared to existing methods. The procedure is validated with closed loop simulation results covering the full operating range of an exemplary MMC.

   Single-Stage Boost Modular Multilevel Converter (BMMC) for Energy Storage Interface
By Ahmed ABDELHAKIM [View]
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Abstract: Single-stage DC-AC power converters are gaining higher attention due to their simpler structure compared to the two-stage equivalent solution. In this paper, a single-stage DC-AC converter solution is proposed for interfacing a low voltage (LV) DC source with a higher voltage AC load or grid, where this converter has a modular structure with multilevel operation. The proposed converter, which is called boost modular multilevel converter (BMMC), comprises the boosting capability within the inversion operation, and it is mainly dedicated for interfacing LV energy storage systems, such as fuel cells and batteries, and it allows the use of LV MOSFETs (inf. 300 V), in order to utilize their low ON-state resistance, along with LV electrolytic capacitors. This converter is introduced and analysed in this paper, where simulation results using PLECS, considering a 10 kW three-phase BMMC, are presented in order to verify its functionality.

EPE 2020 - LS3a: Modular Multilevel 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 - LS3a: Modular Multilevel Converters
	[return to parent folder]

	Direct Multivariable Control for MMC: Digital Signal Processing and Experimental Results By Daniel DINKEL	[View] [Download]
Abstract: Modular Multilevel Converters (MMC) have opened the road for power electronics to many new anddemanding applications in the high power range. The increased degrees of freedom of MMC and thehigher number of variables to be controlled have to be fully used by advanced multivariable control(MVC) concepts. Fast and independent control of all essential variables establishes a solid basis forfully electronic fault management, fault ride through and tight control of the internal arm energies of the converter. The new MVC concept - suitable for MMC with high level count - has been implemented based on FPGA-Hardware and digital signal processing of the measured values. Experimental results of the control performance, using a down scaled MMC with 96 submodules (SM), are presented.

	Energy-Balancing of a Modular Multilevel Converter Using an Online Trajectory Planning Algorithm By Qiuye GUI	[View] [Download]
Abstract: Modular Multilevel Converter (MMC) energy balancing is a nontrivial open-loop control problem, since the choice of a technically meaningful output leads to an internal dynamics. The method used in this paper relies on an MMC arm energy model, which allows algebraic parametrization of almost all system variables and the rest can be obtained by integration of a small subsystem of low order. The solution introduced in this paper is to plan appropriate trajectories for all variables such that the balancing goal is met. The planned trajectories are given to the control system, which leads to a feedforward balancing effort supporting the standard feedback balancing control. In contrast to the previous approach, an analytical solution was obtained providing for efficient real-time trajectory planning. Test bench measurements confirm improved energy control performance compared to standard feedback balancing.

	Reducing the Energy Storage Requirements of Modular Multilevel Converters with Optimal Capacitor Voltage Trajectory Shaping By Simon FUCHS	[View] [Download]
Abstract: The required module capacitance value is a driving factor of the volume and cost of modular multilevel converters (MMC). In order to minimize the required capacitance value, an optimal circulating current and common mode (CM) voltage injection strategy which keeps the conduction losses and die CM voltage as low as possible is proposed in this paper. Unlike previous methods from literature that only focus on minimizing the amplitude of energy fluctuation in the arm capacitors, the proposed optimization procedure is based on the optimal shaping of both the arm voltages and energies. As a result, the proposed optimization scheme achieves a further reduction in the required capacitance value of up to 42\% compared to existing methods. The procedure is validated with closed loop simulation results covering the full operating range of an exemplary MMC.

	Single-Stage Boost Modular Multilevel Converter (BMMC) for Energy Storage Interface By Ahmed ABDELHAKIM	[View] [Download]
Abstract: Single-stage DC-AC power converters are gaining higher attention due to their simpler structure compared to the two-stage equivalent solution. In this paper, a single-stage DC-AC converter solution is proposed for interfacing a low voltage (LV) DC source with a higher voltage AC load or grid, where this converter has a modular structure with multilevel operation. The proposed converter, which is called boost modular multilevel converter (BMMC), comprises the boosting capability within the inversion operation, and it is mainly dedicated for interfacing LV energy storage systems, such as fuel cells and batteries, and it allows the use of LV MOSFETs (inf. 300 V), in order to utilize their low ON-state resistance, along with LV electrolytic capacitors. This converter is introduced and analysed in this paper, where simulation results using PLECS, considering a 10 kW three-phase BMMC, are presented in order to verify its functionality.