| 摘要 |
A method for constant air volume control by direct power control of a PM motor and an HVAC system applying same. The method comprises the following steps: step A) starting a motor controller to receive a target air volume value IN-CFM; step B) obtaining a corresponding function P=f(n) according to the target air volume value IN-CFM; step C) entering a mode of constant air volume control by direct power control: controlling the motor to reach a stable operating point (pt, nt) along a control trajectory of the function P=f(n); step D) calculating real-time input power Pi of the motor according to operating parameters of the motor, and calculating ΔΡ=|Ρ-Pi|; step E) if ΔΡ is less than a set value Pset, maintaining the existing operating point; step F) if ΔΡ is greater than or equal to the set value Pset, calculating operating time of a speed loop to determine whether the operating time expires, and if the time does not expire, maintaining the existing operating point; and step G) if the time expires, entering a speed control loop to adjust the speed and realize a new operating point (Pi, ni) on the trajectory, namely, making pt=Pi and nt=ni, and going back to step C. The method is especially suitable for air volume control in steady state, and has concise algorithms, low requirements on CPU operation, low cost, and high control precision. |
