Shape Memory Alloy Solar Tracker With Precise Incremental Motion

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Solution Overview

Problem

Conventional solar tracking systems using step motors or passive methods are often bulky, expensive, and inefficient, increasing the cost and complexity of solar photovoltaic installations, while existing shape memory alloy systems are limited in precision and application.

Innovation Solution

A solar tracking mechanism utilizing shape memory alloy motors with a novel drive assembly and analog sensor circuit, allowing precise, efficient motion in a single axis, reducing size and cost, and enabling use in various applications beyond solar power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional step motors are used to drive solar tracking, then tracking function is achieved, but the system becomes bulky, heavy, and expensive

Engineering Contradiction:

Improvetracking functionVSAvoidsystem weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent replaces conventional step motors with a shape memory alloy-based actuation system. The shape memory alloy wire undergoes phase transformation under electrical heating to produce mechanical displacement, eliminating the need for traditional mechanical motor components, gears, and associated heavy structure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the temperature-dependent phase transformation properties of shape memory alloys. By controlling the temperature parameter through electrical heating, the alloy transitions between austenite and martensite phases, producing controlled mechanical motion without heavy mechanical actuators.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional step motors are used for solar tracking, then tracking is achieved, but the cost increases substantially

Engineering Contradiction:

Improvetracking functionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive conventional motor assemblies with a simpler shape memory alloy wire-based system. This eliminates the need for motors, gearboxes, controllers, and associated electronics, significantly reducing manufacturing costs while maintaining tracking functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates unnecessary mechanical components from the tracking system. By removing motors, gears, and complex control mechanisms, the system achieves cost reduction while retaining the essential solar tracking function through the intelligent material's inherent properties.

Inventive Principle:

Principle #2Taking out (Extraction)

3Weight of stationary object

If shape memory alloy motors are used, then size and cost are reduced, but precision and control capability must be maintained

Engineering Contradiction:

Improvesystem sizeVSAvoidmotion precision

Core Design Contradiction:

Weight of stationary objectVSMeasurement precision

Solution Approach 1:

The patent incorporates a feedback control system using photodetectors to detect sun position and a control circuit to regulate the heating current applied to the shape memory alloy wire. This closed-loop control ensures precise angular positioning by continuously adjusting the alloy's temperature and thus its length based on actual sun tracking performance.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent precisely controls the temperature parameter applied to the shape memory alloy wire through regulated electrical heating. By controlling the heating duration and power level, the system achieves precise control over the alloy's phase transformation and resulting mechanical displacement, enabling accurate angular positioning.

Inventive Principle:

Principle #35Parameter changes

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 solution increases energy output by 28% and reduces costs by using shape memory alloy motors in a solar tracking system, providing a compact, efficient, and versatile drive mechanism for solar tracking and other applications.

Implementation Method 1

a shape memory alloy motor assembly including a shape memory alloy wire... transforming electrical energy to mechanical energy thereby causing movement of an output shaft

Methodology Applied

Scientific EffectResistive heating: Joule Heating

Implementation Method 2

Shape memory alloys (SMAs), also known as smart materials, have the capability of altering their shape upon the application of heat or electrical current

Methodology Applied

Scientific EffectShape memory alloy effect: Shape Memory Alloy

Data Source

PatentUS7692091B2Shape memory alloy motor as incorporated into solar tracking mechanism

Publication Date: 2010.04.06 ALTAII KARIM

AI summary

The present invention provides a motor driven by shape memory alloys for use in a variety of applications. In the disclosed embodiment, the motor is used to drive a photovoltaic panel so that the panel may remain in appropriate alignment with the sun throughout the day. In such a configuration, the motor assembly relies upon the intrinsic properties of shape memory alloys, in conjunction with a spring assembly, in order to generate sufficient torque in order to rotate the photovoltaic panel. In order to control the orientation of the panel, the system relies upon a sun tracking mechanism which includes an analog sensor circuit, a plurality of phototransistors and a power source. Accordingly, the device is able to rotate the photovoltaic panel in discrete and precise increments as the day progresses.