Motor and pump system
The present system generally relates to a fluid flow system where a controller and motor pump assemblies are used to optimize the control of fluid flow through the system. The controller samples the back electromotive force of the motor and pump assemblies and is able to utilize the sampled back electromotive force in conjunction with predefined target back electromotive force values, preferably empirically determined and tuned to an induvial motor and for a select fluid, to tune the voltage applied to the system, control the back electromotive force of the system and, by extension, control the flow of fluid.
1. A method of controlling the outflow of a computer controlled motor and pump system comprising:
step 1) a computer controller receiving a signal corresponding to a dispense command;
step 2) applying base voltage pulses to a motor of a motor and pump system to drive the motor at a first average voltage, wherein each pulse is comprised of a period of time when voltage is applied followed by a period of time where voltage is not applied;
step 3) measuring a plurality of instantaneous back electromotive force values of the motor over the course of a plurality of pulses, wherein the measurements of each of the plurality of instantaneous back electromotive force values are taken during the period of time of step 2 where voltage is not applied;
step 4) averaging the plurality of instantaneous back electromotive force values to obtain an average back electromotive force value;
step 5) storing the average back electromotive force value in a memory accessible by the controller;
step 6) calculating an adjustment voltage based on the first average voltage, a target back electromotive force, and the average back electromotive force;
step 7) adding the adjustment voltage to the first average voltage to obtain a new run voltage;
step 8) adjusting the pulse width of the base voltage pulses to drive the motor at the new run voltage.
2. The method of controlling the outflow of a computer controlled motor and pump system of claim 1 , wherein the first average voltage is calculated by averaging the voltage applied over a plurality of pulses, and wherein the new run voltage is calculated by averaging the voltage applied over a plurality of pulses.
3. The method of controlling the outflow of a computer controlled motor and pump system of claim 1 further comprising:
stopping the receiving of a signal corresponding to a dispense command;
stopping the motor;
receiving a new signal corresponding to a dispense command;
repeating steps 2 through 8 wherein the first average voltage of repeated step 2 is the new run voltage, and wherein the new run voltage of repeated steps 7 and 8 is a second new run voltage.
4. The method of controlling the outflow of a computer controlled motor and pump system of claim 1 further comprising:
step 9) stopping the receiving of a signal corresponding to a dispense command;
step 10) stopping the motor;
step 11) repeating steps 1 through 10 for a plurality of cycles, wherein one cycle comprises conducting steps 1 through 10 once each and wherein, for each successive cycle, the value of the first average voltage of step 2 is the value of the new run voltage determined during step 7 of the previous cycle.
5. The method of controlling the outflow of a computer controlled motor and pump system of claim 4 , wherein over the course of a plurality of successive cycles, the average of a plurality of successively applied first average voltage values of step 2 diverges from the first average voltage applied during the first cycle of the plurality of cycles.
6. The method of controlling the outflow of a computer controlled motor and pump system of claim 4 wherein, over the plurality of successive cycles, the average back electromotive force value of step 4 remains convergent on the target back electromotive force.
7. The method of controlling the outflow of a computer controlled motor and pump system of claim 4 , wherein, when, over the plurality of successive cycles the average back electromotive force value of step 4 diverges from the target back electromotive force for three consecutive cycles, the controller stops applying the base voltage and indicates an abnormal condition.
8. The method of controlling the outflow of a computer controlled motor and pump system of claim 4 wherein the base voltage remains constant over the plurality of cycles.
9. The method of controlling the outflow of a computer controlled motor and pump system of claim 1 , wherein the measurements of the instantaneous back electromotive force values in step 3 are taken at the midpoint of.
10. The method of controlling the outflow of a computer controlled motor and pump system of claim 3 , wherein the first average voltage of repeated step 2 is different from the new run voltage of repeated steps 7 and 8.
11. The method of controlling the outflow of a computer controlled motor and pump system of claim 3 , wherein the voltage adjustment of step 6 is calculated by dividing the target back electromotive force by a figure derived from the average back electromotive force and multiplying the result by the first average voltage to calculate a theoretical voltage, then subtracting the first average voltage from the theoretical voltage, and then multiplying the result by a percentage.
12. The method of controlling the outflow of a computer controlled motor and pump system of claim 3 , wherein the percentage is 33%.