Adaptive control for motor fan with multiple speed taps
A circulator blower controller for a circulator blower of a heating, ventilation, and air conditioning (HVAC) system of a building includes an interface configured to receive a demand signal with an operating mode from a thermostat. A switching circuit selectively connects power to a tap of a motor of the circulator blower. A data store configured to store a mapping from a speed to the tap. For each tap, a processor observes power consumed by the circulator blower while power is connected to the tap by the switching circuit. The processor determines the mapping by sorting the taps based on observed power consumption. The processor selects a first speed based on the demand signal from the thermostat. The processor identifies a first tap from the mapping based on the first speed and generates the tap selection signal to control the switching circuit to connect power to the first tap.
1. An air handler monitor module for a circulator blower of a heating, ventilation, and air conditioning (HVAC) system of a building, the air handler monitor module comprising:
a memory circuit configured to store a mapping from a plurality of speeds of the circulator blower to a plurality of control signals used to operate a motor of the circulator blower; and
a processor circuit configured to:
determine the mapping by:
for each control signal of the plurality of control signals, observe power consumed by the circulator blower while the control signal is being generated; and
sorting the plurality of control signals in order of observed power consumption; and
in response to receiving a demand signal from a thermostat specifying an operating mode for the HVAC system:
select a first speed based on the demand signal;
use the mapping to identify, from the first speed, a first control signal of the plurality of control signals; and
generate the first control signal to drive the circulator blower at the first speed.
2. A circulator blower system comprising:
the air handler monitor module of claim 1 ; and
the circulator blower, wherein the circulator blower includes (i) the motor and (ii) a fan that is driven by the motor and configured to circulate air within the building.
3. The circulator blower system of claim 2 , wherein the motor comprises at least one of:
an electronically commutated motor (ECM) configured such that the plurality of control signals instructs the ECM to run at different speeds; and
a permanent split capacitor (PSC) motor including a winding and configured such that the plurality of control signals correspond to different taps along the winding.
4. The circulator blower system of claim 2 , wherein the motor comprises:
an electronically commutated motor (ECM);
a plurality of sensors that determine which one or more of the plurality of control signals are activated; and
a speed controller configured to control the ECM to rotate at a speed based on which one or more of the plurality of control signals are activated.
5. The air handler monitor module of claim 1 , wherein the operating mode is selected from a plurality of operating modes that include a cool mode and a fan only mode.
6. The air handler monitor module of claim 5 , wherein the processor circuit is configured to, in response to receiving the demand signal from the thermostat specifying the fan only mode, set the first speed to a speed defined by a user of the building.
7. The air handler monitor module of claim 5 , wherein:
the plurality of operating modes further includes a heat mode; and
the processor circuit is configured to, in response to receiving the demand signal from the thermostat specifying the heat mode, set the first speed to a speed defined by a user of the building.
8. The air handler monitor module of claim 5 , wherein the processor circuit is configured to, in response to receiving the demand signal from the thermostat specifying the cool mode:
select the first speed according to a predetermined initial speed;
after a first predetermined period of time following selection of the first speed, select a second speed that is faster than the first speed; and
in response to selection of the second speed, (i) use the mapping to identify, from the second speed, a second control signal of the plurality of control signals and (ii) generate the second control signal to drive the circulator blower at the second speed.
9. The air handler monitor module of claim 8 , wherein the predetermined initial speed is a lowest speed of the circulator blower.
10. The air handler monitor module of claim 8 , wherein the processor circuit is configured to, in response to receiving the demand signal from the thermostat specifying the cool mode:
after a second predetermined period of time following selection of the second speed, select a third speed that is faster than the second speed; and
in response to selection of the third speed, (i) use the mapping to identify, from the third speed, a third control signal of the plurality of control signals and (ii) generate the third control signal to drive the circulator blower at the third speed.
11. The air handler monitor module of claim 5 , wherein the processor circuit is configured to, in response to the demand signal from the thermostat specifying the cool mode:
select the first speed according to a predetermined initial speed;
evaluate an operating condition of the HVAC system;
in response to the operating condition of the HVAC system meeting a first predetermined criterion, select a second speed that is faster than the first speed; and
in response to selection of the second speed, (i) use the mapping to identify, from the second speed, a second control signal of the plurality of control signals and (ii) generate the second control signal to drive the circulator blower at the second speed.
12. The air handler monitor module of claim 11 , wherein:
the operating condition of the HVAC system is temperature split;
the temperature split is based on a difference between supply air leaving an evaporator coil of the HVAC system and return air arriving at the evaporator coil;
the processor circuit is configured to integrate time periods during which the temperature split diverged from a predetermined temperature profile; and
the first predetermined criterion is the integration exceeding a first threshold.
13. The air handler monitor module of claim 12 , wherein the processor circuit is configured to, in response to determining that a humidity in a conditioned space of the building exceeds a desired humidity, increase the first threshold.
14. The air handler monitor module of claim 12 , wherein the processor circuit is configured to perform the integration by, for each time period during which the temperature split diverged from the predetermined temperature profile, accumulating a product of a gain factor and a length of the time period.
15. The air handler monitor module of claim 12 , wherein the processor circuit is configured to:
in response to selection of the second speed, (i) evaluate the operating condition of the HVAC system and (ii) in response to the operating condition of the HVAC system meeting a second predetermined criterion, select a third speed that is faster than the second speed; and
in response to selection of the third speed, (i) use the mapping to identify, from the third speed, a third control signal of the plurality of control signals and (ii) generate the third control signal to drive the circulator blower at the third speed,
wherein the second predetermined criterion is the integration exceeding a second threshold.
16. The air handler monitor module of claim 11 , wherein the processor circuit is configured to, after a first predetermined period of time following selection of the first speed, select the second speed.
17. The air handler monitor module of claim 16 , wherein the processor circuit is configured to, in response to determining that a humidity in a conditioned space of the building exceeds a desired humidity, increase the first predetermined period of time.
18. The air handler monitor module of claim 5 , wherein the processor circuit is configured to, in response to receiving the demand signal from the thermostat specifying the cool mode:
selectively determine a refrigerant undercharge condition of the HVAC system; and
in response to determining the refrigerant undercharge condition, (i) select a slower speed, (ii) use the mapping to identify, from the slower speed, a second control signal of the plurality of control signals, and (iii) generate the second control signal to drive the circulator blower at the slower speed.
19. The air handler monitor module of claim 1 , wherein:
the processor circuit is configured to, until the mapping includes entries for all of the plurality of control signals, observe the power consumed; and
observing the power consumed includes, while no demand signal is received from the thermostat, iterating through control signals of the plurality of Control signals by generating an evaluation control signal of the plurality of control signals and observing the power consumed while the evaluation control signal is being generated.
20. The air handler monitor module of claim 1 , wherein the processor circuit is configured to, in response to determining that the motor is not operating while the first control signal is being generated, generate a second control signal of the plurality of control signals to drive the circulator blower at a second speed.
21. A circulator blower control system comprising:
the air handler monitor module of claim 1 ; and
a driver circuit configured to drive a plurality of output signals based on the plurality of control signals.
22. The circulator blower control system of claim 21 wherein the number of the plurality of output signals is equal to the number of the plurality of control signals.
23. The circulator blower control system of claim 21 wherein the plurality of output signals is configured to control relays to connect power to corresponding taps of the motor.
24. The air handler monitor module of claim 1 wherein each of the plurality of control signals corresponds to a separate control line connected to the air handler monitor module.
25. The air handler monitor module of claim 1 wherein each of the plurality of control signals corresponds to a unique value of a tap selection output of the air handler monitor module.