System and method of controlling current draw of a switched reluctance motor
View Patent ↗Disclosed is a system and method for controlling current in a switched reluctance motor by changing a dwell state including starting the motor in a normal mode, measuring current in the motor, comparing the measured current to a first threshold, triggering an interrupt if the measured current exceeds the first threshold, keeping a count of consecutive readings exceeding the first threshold, changing the dwell state from a first state to a second state if the measured current exceeds the first threshold and the count equals a set value, changing the dwell state from a second state to a third state if the measured current exceeds a second threshold, and triggering a fault condition if the measured current in the third state exceeds a third threshold.
1. A method for controlling current in a switched reluctance motor by changing a dwell state, the motor receiving power in the range of 9 to 16 Volts DC, the method comprising:
measuring current in the motor;
comparing the measured current to a first threshold;
keeping a count of consecutive readings exceeding the first threshold; and
changing the dwell state from a first state to a second state if the measured current exceeds the first threshold and the count equals a set value.
2. The method of claim 1 ,
wherein the set value is five.
3. The method of claim 1 , wherein the first state is a higher dwell state and the second state is a lower dwell state and wherein the dwell state is changed from a higher state to a lower state when the current is higher than the first threshold.
4. The method claim 3 , wherein the higher dwell state is 95% dwell and the lower dwell state is 85% dwell.
5. The method of claim 3 , further comprising changing the dwell state to a third state if the current exceeds a second threshold.
6. The method of claim 5 , wherein the third dwell state is a higher dwell state and wherein the dwell state is changed from a lower dwell state to a higher dwell state when the current is lower than the second threshold.
7. The method of claim 6 , further comprising changing the dwell state to a fourth state if the current exceeds a third threshold.
8. The method of claim 7 , wherein the fourth state is a fault condition.
9. The method of claim 1 , wherein the first state is a lower dwell state and the second state is a higher dwell state.
10. The method of claim 1 , wherein the first state is a higher dwell state and the second state is a fault condition.
11. The method of claim 10 , wherein the fault condition is triggered if the current is above the first threshold when operating in a higher dwell state.
12. A method for controlling current in a switched reluctance motor by changing a dwell state, the method comprising:
starting the motor in a normal mode;
measuring current in the motor;
comparing the measured current to a first threshold;
triggering an interrupt if the measured current exceeds the first threshold;
keeping a count of consecutive readings exceeding the first threshold;
changing the dwell state from a first state to a second state if the measured current exceeds the first threshold and the count equals a set value;
changing the dwell state from a second state to a third state if the measured current exceeds a second threshold; and
triggering a fault condition if the measured current in the third state exceeds a third threshold.
13. The method of claim 12 wherein the first and third state is a higher dwell state and the second state is a lower dwell state.
14. The method of claim 13 wherein the higher dwell state is 95% dwell and the lower dwell state is 85% dwell.
15. The method of claim 12 wherein the first threshold and the third threshold are equal.
16. The method of claim 12 , wherein a phase of the motor is shut off when the fault condition is triggered.
17. The method of claim 12 , wherein an error code is loaded when the fault condition is triggered.
18. A vacuum cleaner system including a switched reluctance motor, comprising:
a control circuit used to control the operation of the motor;
the control circuit including a microcontroller to control the current by changing a dwell state of the motor; and
the microcontroller running a routine to measure current of the motor, keep a count of consecutive readings exceeding a first threshold, change the dwell state from a first state to a second state if the measured current exceeds a first threshold and the count equals a set value, change the dwell state from a second state to a third state if the measured current exceeds a second threshold, and trigger a fault condition if the measured current while in the third state exceeds a third threshold.
19. The vacuum cleaner system as recited in claim 18 , wherein the first and third state is a higher dwell state and the second state is a lower dwell state.