Aggregate Load Management Using Randomized PWM

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Solution Overview

Problem

Existing energy management methods, such as voltage reductions and rolling blackouts, cause significant disruptions to consumers and cannot adjust power reduction by a controlled amount, leading to equipment damage and quality of life impacts during peak demand periods.

Innovation Solution

A method and system for aggregate load management using randomized pulse width modulation (PWM) to control power-consuming devices, determining load capacity limits, selecting demand reduction targets, and sending control signals to controllers in the utility system to synchronize and randomize the operation of power-consuming devices, thereby managing load demand effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If voltage reductions or rolling blackouts are used to prevent outages during peak demand, then system stability is improved, but consumer quality of life deteriorates and equipment damage occurs

Engineering Contradiction:

Improvesystem stabilityVSAvoidconsumer disruption and equipment damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system implements periodic demand reduction events using randomized pulse width modulation (PWM) to cycle power-consuming devices on and off in a controlled manner. This periodic action prevents continuous overload while avoiding permanent outages, thereby maintaining system stability without causing equipment damage or severe consumer disruption.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the operation of power-consuming devices based on real-time load conditions and capacity limits. By randomly varying the duty cycle of PWM signals, the system creates dynamic load management that adapts to changing conditions, preventing both system overload and harmful disruptions to consumers.

Inventive Principle:

Principle #15Dynamics

2Reliability

If bulk-level load control is applied to reduce peak demand, then system capacity limits are protected, but precise control of power reduction amount is lost

Engineering Contradiction:

Improvecapacity limit protectionVSAvoidcontrolled power reduction adjustment

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system applies different control strategies to different localities or groups of power-consuming devices based on their specific characteristics and the local load conditions. This allows precise control of power reduction amounts in different areas while collectively protecting overall system capacity limits, enabling both reliability and adaptability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes the PWM duty cycle parameter randomly within defined bounds to achieve controlled power reduction. By adjusting this parameter dynamically, the system can precisely control the amount of power reduction while ensuring capacity limits are not exceeded, resolving the contradiction between protection and adaptability.

Inventive Principle:

Principle #35Parameter changes

3Power

If direct load control cycles HVAC systems to reduce demand, then peak load is reduced, but consumer comfort and equipment longevity deteriorate

Engineering Contradiction:

Improvepeak load reductionVSAvoidconsumer comfort and equipment harm

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The system provides beforehand cushioning by maintaining HVAC systems in a ready state and using gentle PWM cycling rather than abrupt on/off control. This approach reduces peak load while minimizing thermal shocks to equipment and maintaining consumer comfort, preventing the harmful effects associated with traditional direct load control.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system replaces traditional mechanical on/off control of HVAC systems with electronic pulse width modulation (PWM) control. This substitution allows for smoother, more gradual power adjustment that reduces peak demand while protecting equipment from mechanical stress and maintaining consumer comfort through controlled temperature management.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9014864B2Aggregate load management at a system level

Publication Date: 2015.04.21 HAIER US APPLIANCE SOLUTIONS INC

AI summary

A method for aggregate load management includes determining whether a load capacity limit within a utility power network will be exceeded, selecting an aggregated demand reduction target to remain within capacity bounds if the load capacity limit is to be exceeded, selecting a demand reduction strategy, and sending a control signal that includes a randomized PWM level, based on the strategy, to a controller in a load component of the utility system based on the reduction target. A method for component load management includes receiving a control signal from a utility system based on a utility demand reduction strategy, converting the signal into randomized PWM control of the load component in accordance therewith, receiving an updated control signal based on utility system monitoring of an aggregate load of a component of the utility system, and converting the updated signal into randomized PWM control of the load component in accordance therewith.