HVAC actuator

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Solution Overview

Problem

HVAC actuators with electric motors face challenges in power supply independence and efficiency, particularly during installation and operation, as they often require extensive wiring and suffer from limited running time with battery power, and initial testing is hindered by the absence of an external power supply.

Innovation Solution

An HVAC actuator with an energy buffer and power limiting circuit that stores electrical energy and controls input power to match motor demands, allowing for reduced power consumption and independent operation, featuring a Lithium-ion capacitor for high energy density and low self-discharge, and an activation switch for initial power-free activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If batteries or accumulators are used to provide power independence, then independency from external power supply is improved, but running time is limited due to discharging processes

Engineering Contradiction:
Improveindependency from external power supplyVSAvoidrunning time
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of moving object

Solution Approach 1:

The energy buffer is pre-charged during periods when power is available (normal operation) so that energy is stored in advance for use during power failures or installation phases. This preliminary energy accumulation enables the actuator to operate independently without immediate connection to external power supply.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the operational parameters by switching between different power sources (mains power during normal operation, energy buffer during power failures). The power limiting circuit dynamically adjusts power consumption parameters to match the available energy in the buffer, extending operational duration.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of moving object

If larger energy storage is used to extend running time, then duration of action is improved, but device complexity and cost increase

Engineering Contradiction:
Improverunning timeVSAvoidenergy storage system complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

Instead of providing continuous full power, the system uses partial action by limiting power consumption to essential functions only during buffer-powered operation. The power limiting circuit ensures that critical motor operations can complete using stored energy without requiring the energy buffer to support full continuous load, thereby reducing buffer size requirements.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system operates in periodic cycles, alternating between charging the energy buffer during normal power availability and discharging it during power failures. This periodic charge-discharge pattern allows a smaller buffer to provide adequate running time by accumulating energy efficiently during charged states.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If power limiting is applied to reduce power consumption, then energy efficiency is improved, but motor power availability may be insufficient during active operation

Engineering Contradiction:
Improvepower consumptionVSAvoidmotor power availability
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The power limiting circuit dynamically adjusts its restrictions based on real-time conditions, including the energy buffer charge level and motor operational state. During motor active periods, the circuit temporarily increases power availability to ensure sufficient torque and speed, then restricts power during idle periods to maximize energy buffer recharge efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system maintains continuous useful action by ensuring the motor can complete its operational cycle (activate, perform function, deactivate) without interruption. The power limiting circuit is designed to provide adequate power throughout the entire motor active period, preventing mid-operation power cutoffs that would compromise the useful action.

Inventive Principle:
Principle #20Continuity of useful action

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 solution enhances power supply independence and efficiency by storing energy for later use, reducing the need for large power supplies, enabling smaller and cheaper solutions, and ensuring continuous operation even without external power, while preventing accidental motor movements due to degraded energy buffer performance.

Implementation Method 1

an energy buffer (13) configured to store electrical energy from a power supply (2) and to provide the electrical energy to the motor (11)

Methodology Applied
Scientific EffectElectrical energy storage: Capacitance

Implementation Method 2

a power limiting circuit (12) configured to limit input power from the power supply (2) to the energy buffer (13) to a threshold lower than motor power drawn by the motor (11) from the energy buffer (13)

Methodology Applied
Scientific EffectPower limiting: Electrical Resistance

Data Source

PatentEP3551943B1HVAC actuator
Publication Date: 2021.04.14 BELIMO HOLDING AG
  • EP3551943B1 patent drawingFigure 1
  • EP3551943B1 patent drawingFigure 2
  • EP3551943B1 patent drawing

AI summary

An HVAC actuator (1) comprises an electric motor (11); an energy buffer (13) configured to store electrical energy from a power supply (2), and to provide the electrical energy to the motor (11); and a power limiting circuit (12) configured to limit input power from the power supply (2) to the energy buffer (13) to a threshold lower than motor power drawn by the motor (11 ) from the energy buffer (13).