Method of constant airflow control for a ventilation system
First Claim
1. A method of operating an electric motor in a ventilation system, the method comprising:
- providing a first target value and a second target value;
detecting an electric current applied to the motor;
detecting a rotational speed of the motor;
computing a value of the product by multiplying the detected current and the detected speed;
determining whether the detected electric current is greater or smaller than a reference value;
when determined that the detected electric current is greater than the reference value, controlling the motor'"'"'s operation to adjust the computed product value toward the first target value; and
when determined that the detected electric current is smaller than the reference value, controlling the motor'"'"'s operation to adjust the rotational speed toward the second target value,wherein controlling the motor'"'"'s operation comprises transitioning between adjusting the computed product and adjusting the detected rotational speed of the motor in response to the change between a first state, in which the detected electric current is greater than the reference value, and a second state, in which the detected electric current is smaller than the reference value.
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0 Petitions
Accused Products
Abstract
A method of constant airflow control includes various controls to accomplish a substantially constant airflow rate over a significant change of the static pressure in a ventilation duct. One control is a constant I·RPM control, which is primarily used in a low static pressure range. Another control is a constant RPM control, which is primarily used in a high static pressure range. These controls requires neither a static pressure sensor nor an airflow rate sensor to accomplish substantially constant airflow rate while static pressure changes. Also, the method improves the accuracy of the control by correcting certain deviations that are caused by the motor'"'"'s current—RPM characteristics. To compensate the deviation, the method adopts a test operation in a minimum static pressure condition. Also disclosed is an apparatus for conducting these control methods.
143 Citations
20 Claims
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1. A method of operating an electric motor in a ventilation system, the method comprising:
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providing a first target value and a second target value; detecting an electric current applied to the motor; detecting a rotational speed of the motor; computing a value of the product by multiplying the detected current and the detected speed; determining whether the detected electric current is greater or smaller than a reference value; when determined that the detected electric current is greater than the reference value, controlling the motor'"'"'s operation to adjust the computed product value toward the first target value; and when determined that the detected electric current is smaller than the reference value, controlling the motor'"'"'s operation to adjust the rotational speed toward the second target value, wherein controlling the motor'"'"'s operation comprises transitioning between adjusting the computed product and adjusting the detected rotational speed of the motor in response to the change between a first state, in which the detected electric current is greater than the reference value, and a second state, in which the detected electric current is smaller than the reference value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of operating an electric motor in a ventilation system, the method comprising:
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providing a blower comprising a motor and a fan coupled to the motor, the blower being configured to generate an airflow in a ventilation duct; providing a first target value and a second target value; detecting an electric current applied to the motor; detecting a rotational speed of the motor; computing a value of the product of the detected electric current and the detected speed; determining whether the detected electric current is greater or smaller than a reference value; and controlling the motor'"'"'s operation, which comprises; when determined that the detected electric current is greater than the reference value, adjusting the electric current applied to the motor so as to move the computed product value toward the first target value; and when determined that the electric current is smaller than the reference value, adjusting the electric current so as to move the rotational speed toward the second target value, wherein controlling the motor'"'"'s operation comprises transitioning between moving the computed product and moving the detected rotational speed of the motor in response to the change between a first state, in which the detected electric current is greater than the reference value, and a second state, in which the detected electric current is smaller than the reference value. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification