Interleaved Half-Bridge Submodules with Sensorless Leg Current Balancing in Modular Multilevel Converters

A new state observer-based current balancing method for Modular Multilevel Converters with Interleaved half-bridge Sub-Modules (ISM-MMC) is presented in this paper. The developed observer allows estimating currents through interleaved half-bridge legs in each submodule of ISM-MMC basing only on arm current and submodule’s capacitor voltage measurements. Then, the interleaved current balancing control uses the estimated currents to reduce the interleaved currents imbalance caused by upstream control actions. This technique minimizes the number of required current sensors in ISM-MMC, thereby reducing the converter's cost, weight, and volume. Capabilities of the proposed interleaved currents sensorless balancing control has been tested against standard parameter tolerances of the composing passive elements. The feasibility of the proposed method is verified by extensive simulation and experimental tests.

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Current Balancing Control for Interleaved Half-Bridge Submodules in Modular Multilevel Converters

10.36227/techrxiv.16645861 ◽

2021 ◽

Author(s):

Aleksandr Viatkin ◽

Mattia Ricco ◽

Riccardo Mandrioli ◽

Tamas Kerekes ◽

Remus Teodorescu ◽

...

Keyword(s):

Dynamic Performance ◽

Experimental Tests ◽

Current Control ◽

System Response ◽

Loop Current ◽

Multilevel Converters ◽

Voltage Balancing ◽

Modular Multilevel Converters ◽

Capacitor Voltage ◽

Balancing Control

This paper presents a closed-loop current balancing control for Modular Multilevel Converters with Interleaved half-bridge Sub-Modules (ISM-MMC). The new control loop solves the well-known problem of proper current balancing among interleaved half-bridge legs in each ISM-MMC submodule while preserving a simple and reliable structure. In addition to that, a novel capacitor voltage balancing strategy for MMCs is developed. The new algorithm contains main advantages of the classical capacitor voltage balancing methods while provides an opportunity to decouple two balancing tasks of ISM-MMC, namely capacitor voltage and interleaved legs current balancing. The proposed control methods feature good dynamic performance and are compliant with a digital processor's operational constraints. The effectiveness of the new balancing methods was verified during extensive numerical simulations and experimental tests on a laboratory prototype by the corresponding system response under the input/output characteristics variation and interleaved current control perturbation.

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Current Balancing Control for Interleaved Half-Bridge Submodules in Modular Multilevel Converters

10.36227/techrxiv.16645861.v2 ◽

2021 ◽

Author(s):

Aleksandr Viatkin ◽

Mattia Ricco ◽

Riccardo Mandrioli ◽

Tamas Kerekes ◽

Remus Teodorescu ◽

...

Keyword(s):

Dynamic Performance ◽

Experimental Tests ◽

Current Control ◽

System Response ◽

Loop Current ◽

Multilevel Converters ◽

Voltage Balancing ◽

Modular Multilevel Converters ◽

Capacitor Voltage ◽

Balancing Control

This paper presents a closed-loop current balancing control for Modular Multilevel Converters with Interleaved half-bridge Sub-Modules (ISM-MMC). The new control loop solves the well-known problem of proper current balancing among interleaved half-bridge legs in each ISM-MMC submodule while preserving a simple and reliable structure. In addition to that, a novel capacitor voltage balancing strategy for MMCs is developed. The new algorithm contains main advantages of the classical capacitor voltage balancing methods while provides an opportunity to decouple two balancing tasks of ISM-MMC, namely capacitor voltage and interleaved legs current balancing. The proposed control methods feature good dynamic performance and are compliant with a digital processor's operational constraints. The effectiveness of the new balancing methods was verified during extensive numerical simulations and experimental tests on a laboratory prototype by the corresponding system response under the input/output characteristics variation and interleaved current control perturbation.

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Current Balancing Control for Interleaved Half-Bridge Submodules in Modular Multilevel Converters

10.36227/techrxiv.16645861.v1 ◽

2021 ◽

Author(s):

Aleksandr Viatkin ◽

Mattia Ricco ◽

Riccardo Mandrioli ◽

Tamas Kerekes ◽

Remus Teodorescu ◽

...

Keyword(s):

Dynamic Performance ◽

Experimental Tests ◽

Current Control ◽

System Response ◽

Loop Current ◽

Multilevel Converters ◽

Voltage Balancing ◽

Modular Multilevel Converters ◽

Capacitor Voltage ◽

Balancing Control

This paper presents a closed-loop current balancing control for Modular Multilevel Converters with Interleaved half-bridge Sub-Modules (ISM-MMC). The new control loop solves the well-known problem of proper current balancing among interleaved half-bridge legs in each ISM-MMC submodule while preserving a simple and reliable structure. In addition to that, a novel capacitor voltage balancing strategy for MMCs is developed. The new algorithm contains main advantages of the classical capacitor voltage balancing methods while provides an opportunity to decouple two balancing tasks of ISM-MMC, namely capacitor voltage and interleaved legs current balancing. The proposed control methods feature good dynamic performance and are compliant with a digital processor's operational constraints. The effectiveness of the new balancing methods was verified during extensive numerical simulations and experimental tests on a laboratory prototype by the corresponding system response under the input/output characteristics variation and interleaved current control perturbation.

Download Full-text