Method for driving an actuator of an hvac system

Abstract

A method for driving an actuator of an HVAC system is provided, and which comprises the steps of: a] determining an actuation command to the actuator; and b] ramping a drive power to the actuator between a steady-state-velocity drive power and a zero-velocity drive power to effect a required acceleration or deceleration to a movable member of the HAVC system without or substantially without over-powering of the actuator. An HVAC system is also provided. The HVAC system implementing the above method is not only capable of reducing the noise produced by an HVAC system, but is also capable of reducing an over-powering of the actuator when there is a low load on the system.

1 . A method for driving an actuator of an HVAC system, the method comprising the steps of:
 a] deter mining an actuation command to the actuator; and   b] ramping a drive power to the actuator between a steady-state-velocity drive power and a zero-velocity drive power to effect a required acceleration or deceleration to a movable member of the HAVC system without or substantially without over-powering of the actuator.   
     
     
         2 . The method as claimed in  claim 1 , wherein the drive power to the actuator is smoothly ramped. 
     
     
         3 . The method as claimed in  claim 1 , wherein the actuation command is at least one of initialisation command, final deactivation command and directional-change command to the actuator. 
     
     
         4 . The method as claimed in  claim 1 , wherein, during the step b], the drive power is increased from a zero-velocity drive power until the movable member begins moving. 
     
     
         5 . The method as claimed in  claim 4 , wherein, the step b] further comprising the step of monitoring a position of the movable member, wherein the position of the movable member is indirectly monitored via a position sensor associated with the actuator. 
     
     
         6 . The method as claimed in  claim 1 , further comprising a step prior to the step b] of calculating a required acceleration or deceleration of the actuator to effect the actuation command at the movable member. 
     
     
         7 . The method as claimed in  claim 1 , wherein, during the step b], the drive power to the actuator is automatically ramped between the steady-state-velocity drive power and the zero-velocity drive power upon mechanical play of the HVAC system. 
     
     
         8 . The method as claimed in  claim 7 , wherein the mechanical play is a lost motion of the movable member in the HVAC system caused by many gaps between mechanical components, the method further comprising obtaining positions and lengths of the gaps, during the step b, ramping a drive power according to the positions and lengths of the gaps. 
     
     
         9 . The method as claimed in  claim 7 , further comprising obtaining a parameter representing the mechanical play in the HVAC system, during the step b, ramping a drive power according to the parameter. 
     
     
         10 . The method as claimed in  claim 9 , wherein the actuator comprises at least one rotatable element, the parameter being a total rotation angle of the rotatable element or a total rotation angle of the movable member corresponding to the mechanical play; during the step b, the change of the drive power based on the total rotation angle of the rotatable element or the total rotation angle of the movable member. 
     
     
         11 . The method as claimed in  claim 7 , wherein an information of the mechanical play is pre-programmed. 
     
     
         12 . The method as claimed in  claim 11 , wherein the information of the mechanical play is determined by machine learning during operation or pre-testing of the HVAC system. 
     
     
         13 . The method as claimed in  claim 1 , wherein during step b], the required acceleration or deceleration is at least in part based on a percentage of mechanical play which must be accommodated. 
     
     
         14 . The method as claimed in  claim 1 , further comprising a step of monitoring directionality of a travel of the actuator. 
     
     
         15 . The method as claimed in  claim 1 , wherein the movable member of the HVAC system comprises at least one HVAC vent flap. 
     
     
         16 . A method for driving an actuator of an HVAC system, the method comprising the steps of:
 a] determining a region of mechanical play in a movable member of the HVAC system which is associated with the actuator;   b] monitoring a position of the movable member or at least one rotatable element of the actuator to detetiiiine when the region of mechanical play has been entered or exited; and   c] ramping a drive power to the actuator between a steady-state-velocity drive power and a zero-velocity drive power during the region of mechanical play so as to eliminate or reduce over-powering of the actuator.   
     
     
         17 . An HVAC system comprising:
 an actuator having an actuator position sensor associated therewith;   at least one HVAC vent flap connected to the actuator via a movable member, the motion of the movable member having a region of mechanical play therein;   a controller for controlling the actuator; and   a memory circuit associated with the controller and arranged to store information of the region of mechanical play; the controller being adapted to ramp a drive power to the actuator between a steady-state-velocity drive power and a zero-velocity drive power when the actuator position sensor determines that the motion of the movable member is within the region of mechanical play.   
     
     
         18 . The HVAC system as claimed in  claim 17 , wherein the mechanical play is a lost motion of the movable member in the HVAC system caused by many gaps between mechanical components, the memory circuit is used for storing positions and lengths of the gaps, and the controller is adapted to ramp a drive power according to the positions and lengths of the gaps. 
     
     
         19 . The HVAC system as claimed in  claim 17 , wherein the memory circuit is used for storing a parameter representing the region of mechanical play in the HVAC system, and the controller being adapted to ramp a drive power according to the parameter. 
     
     
         20 . The HVAC system as claimed in  claim 19 , wherein the actuator comprises at least one rotatable element, the parameter being a total rotation angle of the rotatable element or a total rotation angle of the movable member corresponding to the region of mechanical play;
 and the change of the drive power based on the total rotation angle of the rotatable element or the total rotation angle of the movable member.