Synchronous Inverter With Field Control for Constant Output Frequency

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Solution Overview

Problem

Existing engine-generator sets struggle to maintain a constant output frequency while allowing the engine speed to vary, leading to inefficiencies in fuel consumption, wear, and emissions, as they require fixed-speed operation to compensate for load variations.

Innovation Solution

A synchronous inverter system with a controlled field alternator and segmented waveform converter that adjusts the output frequency and voltage by actively controlling the field current, enabling variable engine speeds and efficient power management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the engine operates at a fixed speed to maintain constant output frequency, then the output frequency is stable, but fuel consumption increases and engine wear increases

Engineering Contradiction:

Improveoutput frequency stabilityVSAvoidfuel consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameters of the engine by allowing speed variation while using a frequency converter to maintain stable output frequency. This decouples the direct relationship between engine speed and output frequency, enabling the engine to operate at lower speeds for improved fuel efficiency while the converter ensures frequency stability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The frequency converter acts as an intermediary between the variable-speed engine and the electrical load. It mediates the relationship by accepting variable frequency input from the engine and providing constant frequency output to the load, thus resolving the contradiction between engine speed flexibility and frequency stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the engine operates at a fixed speed to maintain constant output frequency, then the output frequency is stable, but engine wear increases

Engineering Contradiction:

Improveoutput frequency stabilityVSAvoidengine wear

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The system allows the engine speed parameter to vary within an optimal range rather than being fixed, reducing mechanical stress and wear. The frequency converter compensates for speed variations to maintain stable output, enabling the engine to operate more reliably with reduced wear.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If the engine speed decreases at light loads to reduce fuel consumption, then fuel efficiency improves, but output frequency becomes variable

Engineering Contradiction:

Improvefuel consumptionVSAvoidoutput frequency stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The frequency converter dynamically adjusts its conversion ratio to maintain constant output frequency regardless of the variable engine speed. This allows the engine to operate at lower speeds for improved fuel efficiency while the converter ensures the output frequency remains stable and suitable for electrical loads.

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If conventional frequency conversion methods are used, then variable engine speed is enabled, but total harmonic distortion increases

Engineering Contradiction:

Improveengine speed variabilityVSAvoidtotal harmonic distortion

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces conventional mechanical frequency conversion methods with an electrically-controlled switched reluctance motor system. This substitution enables variable engine speed operation while maintaining lower total harmonic distortion through precise electronic control of the motor phases and switching sequences.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The system allows for efficient power management by maintaining a constant output frequency, reducing fuel consumption, wear, and emissions, while using lower-rated components and minimizing total harmonic distortion.

Implementation Method 1

A synchronous inverter system with a controlled field alternator and segmented waveform converter that adjusts the output frequency and voltage by actively controlling the field current

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

segmented waveform converter that adjusts the output frequency and voltage by actively controlling the field current

Methodology Applied

Scientific EffectWaveform synthesis:

Data Source

PatentUS12368399B2Synchronous inverter

Publication Date: 2025.07.22 DISCOVERY ENERGY LLC

AI summary

An apparatus includes a first inverter circuit and a second inverter circuit. The first invertor circuit is configured to couple an alternator and a load device to deliver a driving signal from the alternator to the load device. The second invertor circuit is configured to couple the alternator to the load device to deliver a driving signal from the alternator to the load device and configured to couple a battery to the alternator to deliver a charging signal from the alternator to the battery.