Medium-Voltage Vessel Charging with Series Compensation Control

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Solution Overview

Problem

Existing marine vessel charging systems require large, heavy, and expensive converters, leading to high power losses and increased footprint, and lack compatibility with standard MVAC networks, necessitating a more efficient and compact onboard charging solution.

Innovation Solution

An onboard medium-voltage vessel electric charging apparatus using a rectifier unit with a rectifier transformer and controllable compensation unit, which includes a compensation transformer and converter, to adjust AC voltage and deliver controlled DC current, enabling connection to standard MVAC grids and independent power regulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If large converters are used for AC to DC power conversion on marine vessels, then power conversion capability is improved, but equipment footprint, weight, and cost increase

Engineering Contradiction:

Improvepower conversion capabilityVSAvoidequipment footprint

Core Design Contradiction:

PowerVSArea of stationary object

Solution Approach 1:

The patent divides the power conversion system into separate functional modules: a rectifier unit for AC to DC conversion and a compensation unit for power factor correction. This segmentation allows each module to be optimized independently and reduces the overall footprint compared to a single large converter

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The compensation unit serves multiple functions: it provides power factor correction, enables independent charging power regulation, and allows connection to standard MVAC networks. This multi-functionality eliminates the need for separate dedicated equipment for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Power

If large converters are used for AC to DC power conversion on marine vessels, then power conversion capability is improved, but weight increases

Engineering Contradiction:

Improvepower conversion capabilityVSAvoidconverter weight

Core Design Contradiction:

PowerVSWeight of moving object

Solution Approach 1:

By segmenting the power conversion system into a rectifier unit and a compensation unit, each with smaller individual power ratings, the total weight is reduced compared to a single large converter handling the full power conversion task

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operating parameters by using a compensation unit that can independently regulate charging power and provide power factor correction, allowing the rectifier unit to be smaller and lighter while maintaining overall system capability

Inventive Principle:

Principle #35Parameter changes

3Power

If large converters are used for AC to DC power conversion on marine vessels, then power conversion capability is improved, but power losses increase

Engineering Contradiction:

Improvepower conversion capabilityVSAvoidpower losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The segmentation of power conversion functions into separate rectifier and compensation units reduces power losses by allowing each unit to operate at optimal loading conditions and reducing the need for oversized components that operate inefficiently at partial load

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The compensation unit dynamically adjusts operating parameters including power factor and charging power, optimizing efficiency across varying load conditions and reducing overall power losses compared to fixed-parameter large converters

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If standard MVAC network connection is enabled, then adaptability is improved, but additional electrical equipment is required

Engineering Contradiction:

Improvenetwork compatibilityVSAvoidelectrical equipment

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The compensation unit is designed as a multi-functional device that simultaneously provides power factor correction, enables standard MVAC network connection, and allows independent charging power regulation. This universal design adds adaptability without requiring multiple separate specialized equipment

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Reduces equipment footprint and costs, minimizes power losses, and allows marine vessels to connect to standard MVAC networks while independently regulating charging power, using mostly passive components and compact, efficient diode rectifiers.

Implementation Method 1

capable of rectification of the AC power supply and delivery of controlled DC current for charging of an onboard energy storage device

Methodology Applied

Scientific EffectRectification:

Implementation Method 2

The controllable compensation unit is configured to compensate for voltage variations of the vessel DC consumer network or at least one energy storage device by adding a series voltage phasor with different amplitude and phase angle to supplied AC voltage

Methodology Applied

Scientific EffectSeries compensation:

Implementation Method 3

to adjust rectifier voltage of the rectifier unit

Methodology Applied

Scientific EffectVoltage adjustment:

Data Source

PatentUS12459389B2Onboard medium-voltage vessel electric charging apparatus and method for onboard charging

Publication Date: 2025.11.04 KONGSBERG MARITIME AS

AI summary

Onboard medium-voltage vessel electric charging apparatus and method for onboard medium-voltage charging enabling compensating for voltage variations of at least one energy storage device during charging thereof.