Interleaved Pulsed Alternator Current Ripple Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional pulsed alternator systems with multiple pairs produce a load current pulse with significant ripple, which is undesirable for high-energy electromagnetic launcher applications like rail guns that require smooth DC current for precise projectile acceleration and control.

Innovation Solution

The system employs an interleaved pulse control mechanism, where the current outputs from multiple pairs of pulsed alternators are timed to overlap such that the peaks of one pair align with the troughs of another, reducing the ripple effect and improving the smoothness of the load current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If identical gating pulses are sent to rectifier switches for each pulsed alternator, then all output current from each alternator is added together for the highest possible output current, but a load current pulse with significant ripple is produced

Engineering Contradiction:

Improveoutput currentVSAvoidcurrent smoothness

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The patent applies periodic action by implementing interleaved pulse gating where rectifier switches of different pulsed alternators are triggered at different phases within the AC cycle. Specifically, while one alternator pair is at peak current output, another alternator pair is at a different phase, creating a staggered periodic pattern that smooths the combined DC output current and reduces ripple while maintaining high power output.

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If multiple pairs of pulsed alternators are used to store and release higher energy, then the energy storage capacity increases, but the system complexity increases

Engineering Contradiction:

Improveenergy storageVSAvoidsystem complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges multiple pulsed alternator pairs into a single integrated system where all alternators share common prime mover(s) and contribute to a unified DC output through the rectifier bank. This combining approach increases energy storage capacity while managing complexity through coordinated control of the interleaved gating scheme rather than completely independent systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system implements multi-functionality by using the same hardware components (rectifier switches, alternators) to serve dual purposes: generating high power output current while simultaneously smoothing the waveform through interleaved operation. The control system universally manages all alternator pairs with a coordinated gating strategy that achieves both energy delivery and current quality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If pulsed alternators operate in phase with identical gating, then the control mechanism is simple, but the current ripple is significant

Engineering Contradiction:

Improvecontrol simplicityVSAvoidcurrent smoothness

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent introduces dynamics into the control system by implementing time-varying, phase-shifted gating signals for different alternator pairs. Rather than static identical gating, the system dynamically adjusts the triggering phase of each alternator pair's rectifier switches, creating a moving pattern of current contribution that maintains smooth output while preserving operational simplicity through systematic phase distribution.

Inventive Principle:

Principle #15Dynamics

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

This approach reduces the maximum peak-peak load current ripple by 70%, resulting in a more controlled and smooth DC pulse, enhancing the accuracy and efficiency of electromagnetic launcher operations.

Implementation Method 1

specialized rotating generators can be used to store kinetic energy and convert it to high current electrical energy in the millisecond time frame

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

These rail guns use a pulsed power system to launch a projectile very long distances with a high degree of accuracy

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentUS7832385B1Ripple reduction in electromagnetic launcher current from pulsed alternators

Publication Date: 2010.11.16 CURTISS WRIGHT ELECTRO MECHANICAL CORP

AI summary

Systems and methods for improving the current pulse from multiple pairs of pulsed alternators used for driving large loads such as an electromagnetic launcher (i.e., “rail gun”) load. Conventional current pulse ripples are reduced by interleaving pulses from multiple pairs of contra-rotating pulsed alternators. Current pulses supplied by different pairs of pulsed alternators are timed so that they are interspersed between one another to provide more pulses for a given launch time. The interleaved current pulses increase the frequency and reduce the magnitude of the ripple on the average load current.