Variable air volume environmental management system including a fuzzy logic control system

Abstract

A controller for a variable air volume terminal of a variable air volume air conditioning system which comprises a temperature sensing circuitry for generating a temperature process value, a setpoint determining circuitry for establishing a temperature setpoint, an airflow signal circuitry for generating an airflow setpoint in response to the temperature process value and the temperature setpoint. A flow sensing circuitry for generating a flow process value in response to a predetermined set of flow sensing inputs and damper control circuitry for generating a damper motor operation signal to control the damper motor in response to the flow process value and the airflow setpoint. The damper control circuitry comprises a fuzzy logic control mechanism for implementing a set of fuzzy logic rule-based instructions in generating the damper motor operating signal.

Description

TECHNICAL FIELD OF THE INVENTIONThe present invention relates to control systems for environments such as office buildings and commercial establishments, and more particular, to a variable air volume (VAV) environmental management system that integrates a fuzzy logic control system in a stand-alone package for providing all necessary functions of a VAV terminal that may be easily networked into a complex environmental management system and that uses fuzzy logic to provide precise temperature control with the minimal amount of system setup.BACKGROUND OF THE INVENTIONA variable air volume (VAV) environmental management or air conditioning system modulates the amount of air that flows to different offices or locations within an environment such as an office building or other dwelling structure where numerous people live or work. By maintaining constant the temperature that flows through dampers of the air conditioning system and, instead adjusting the position of the damper or the volu...

AI Technical Summary

Benefits of technology

A technical advantage of the present invention is that it provides in a single module a control device for operating the damper actuator motor of a VAV air conditioning system. The present invention is so compact that it may be positioned on the damper actuator motor itself, instead of at a remote site in a separate control circuitry chassis. The present invention incorporates advanced packaging technology to eliminate the need for a large printed circuit board chassis that conventional VAV terminal controllers require. A VAV air conditioning system that employs the present invention, therefore, is easier to install, operate, and maintain than systems that use conventional microprocessor-based VAV terminal controllers.

Problems solved by technology

As a result, compensating for temperature differences in one location frequently generates air flow problems in other locations within the environment.

The air conditioning system, in these instances, operates in less than an ideal mode.

There are, however, significant limitations that associate with existing microprocessor-based VAV terminal controllers.

Significant limitations of existing microprocessor-based VAV terminal controllers are, for example, that the systems are bulky and include large printed circuit boards that mount within separate controller chassis.

Local area networks, however, are not designed for communicating control system data within a control system architecture.

These local area networks inefficiently communicate temperature, pressure and other variable values from one location to another and to a central file server.

Another limitation associated with existing microprocessor-based VAV terminal controllers is the use of complicated instruction sets for generating the desired damper actuator control signal.

The PID algorithm itself is complex and requires significant computational resources to generate the desired damper motor operating signal.

The complexity of the PID algorithm requires significant setup time for each of the locations within the office or commercial environment.

The setup time and inherent complexity of the algorithm makes such systems prone to error and highly susceptible to less than optimal performance.

Images