PM motor direct power control constant-air-volume control method and HVAC system using same

Abstract

The invention discloses a PM motor direct power control constant-air-volume control method and an HVAC system using same. The control method comprises the steps of step A, receiving the target air volume IN-CFM through a starting motor; step B, obtaining a corresponding function P=f (n) according to the target air volume IN-CFM; step C, entering a direct power control constant-air-volume control mode: controlling the motor to reach a stable work point (pt, nt) along the function P=f (n) control track; step D, calculating motor real-time input power Pi according to motor operation parameters, wherein delta P= / Pt-Pi / ; step E, maintaining the prior work point if delta P is smaller than the set value Pset; step F, calculating whether the speed ring operation time is reached if delta P is larger than or equal to the set value Pset, and maintaining the prior work point if the operation time is not reached; step G, entering the speed control circuit adjusting speed, that is, making pt=Pi and nt=ni, if the time is reached to achieve a novel work point (Pi, ni) on the track, and returning to the step C. The control method and the HVAC system have the advantages that the method is particularly applicable to air volume control in the steady state, the algorithm is concise, the requirement for CPU operation is not high, the cost is low, and the control accuracy is high.

Description

Technical field:

[0001] The invention relates to a constant air volume control method for a variable speed motor, in particular to a constant air volume control method for direct power control of a PM motor and the HVAC system and other variable speed motor systems to which it is applied. Background technique:

[0002] PM motor, the abbreviation of brushless DC permanent magnet synchronous motor, can also be called ECM motor. Because the PM motor is used in different environments, its control modes are also different. Generally, there are: constant speed control, constant torque control and constant air volume control. Air volume control is a more commonly used mode in HVAC (heating ventilation system).

[0003] In the indoor ventilation ducts of domestic air conditioners, the static pressure often changes over time, for example due to dust accumulation in the ducts or clogged filters. The static pressure is also often higher than the standard static pressure of the manufac...

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