High Voltage DC Generator Neutral Node Control

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Solution Overview

Problem

Permanent magnet generators in high voltage DC power systems face issues with uncontrolled excitation and undesirable operation during short circuit conditions, leading to potential damage and imbalanced power output.

Innovation Solution

Incorporating a selectively removable neutral node and independent control of control windings connected to a DC power source via power converters, such as PWM inverters and asymmetric H-bridges, to detect and prevent short circuits and balance power output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a permanent magnet generator is used to generate high voltage DC power, then high power density is achieved, but uncontrolled excitation leads to undesirable operation during short circuit conditions

Engineering Contradiction:
Improvepower densityVSAvoidshort circuit operation
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent extracts the neutral node from the permanent magnet generator system during short circuit conditions by opening a switch. This separation removes the harmful uncontrolled excitation path while preserving the generator's high power density capability during normal operation. The neutral node is selectively disconnected to prevent damage during faults.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent makes the neutral node connection dynamic by introducing a controllable switch that can transition between closed (normal operation) and open (short circuit protection) states. This dynamic configuration allows the system to adapt its excitation control based on operating conditions, resolving the contradiction between maintaining power density and ensuring reliability.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the neutral node is permanently connected in a poly-phase permanent magnet generator, then continuous power generation is maintained, but phase imbalances and short circuit damage occur

Engineering Contradiction:
Improvecontinuous power generationVSAvoidphase imbalance and short circuit damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by detecting short circuit conditions and phase imbalances before they cause damage, then preemptively opening the neutral node switch to prevent harmful effects. This proactive protection maintains continuous power generation during normal operation while preventing damage during abnormal conditions.

Inventive Principle:
Principle #9Preliminary anti-action

3Stability of the object's composition

If control windings are independently controlled for each phase, then phase balance is improved, but device complexity increases

Engineering Contradiction:
Improvephase balanceVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing independent control windings for each phase of the poly-phase generator. Each control winding can be independently adjusted to correct phase imbalances, creating localized control capability that stabilizes the three-phase output without requiring complete system redesign.

Inventive Principle:
Principle #3Local quality

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

Prevents power generation during short circuits and corrects phase imbalances, ensuring safe operation and balanced power delivery in high voltage DC power systems.

Implementation Method 1

Permanent magnet generators convert mechanical input power of rotational motion into electrical output power via known interactions between the magnetic field of a permanent magnet and an armature winding

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3255780B1High voltage DC power generating system including selectively removable neutral node
Publication Date: 2023.03.22 HAMILTON SUNDSTRAND CORP
  • EP3255780B1 patent drawingFigure 1
  • EP3255780B1 patent drawingFigure 2
  • EP3255780B1 patent drawingFigure 3

AI summary

A high voltage DC electric power generating system includes a poly-phase permanent magnet generator (110) having at least one control winding (142) and a plurality of power windings (112). Each of the power windings is a phase of the poly-phase permanent magnet generator. A passive rectifier (160) connects a switch (162) to an input of each of the power windings such that the switch is a neutral node in a closed state and a disconnect in an open state.