Abstract: Provided are a method for performance parameter recording and apparatus, a frequency inverter, an air conditioner, and a storage medium. The method includes: obtaining first sampling data by sampling a performance parameter of the frequency inverter based on a first predetermined sampling period; obtaining second sampling data by sampling a performance parameter of the frequency inverter based on a second predetermined sampling period, in which the first predetermined sampling period is smaller than the second predetermined sampling period; and storing, in response to a fault in the frequency inverter, fault data prior to and subsequent to the fault in the frequency inverter, in which the fault data includes the first sampling data and the second sampling data. By using the method, it is possible to analyze a cause of the fault in the frequency inverter conveniently.

Abstract: A method and for controlling a draught fan including: obtaining an actual rotating speed, an actual power, and a target air volume of the draught fan, obtaining a target power corresponding to the target air volume according to the actual rotating speed and the target air volume, obtaining, in response to a power difference value between the actual power and the target power being not within an initial difference value range, a control duration and a rotating speed step size corresponding to the power difference value, and adjusting the actual rotating speed according to the rotating speed step size after the control duration. A dynamic adjustment of the air volume of the draught fan is achieved, and a constant air volume control of the draught fan with low cost, high control accuracy, fast adjustment speed and good stability is achieved.

Abstract: A method and for controlling a draught fan including: obtaining an actual rotating speed, an actual power, and a target air volume of the draught fan, obtaining a target power corresponding to the target air volume according to the actual rotating speed and the target air volume, obtaining, in response to a power difference value between the actual power and the target power being not within an initial difference value range, a control duration and a rotating speed step size corresponding to the power difference value, and adjusting the actual rotating speed according to the rotating speed step size after the control duration. A dynamic adjustment of the air volume of the draught fan is achieved, and a constant air volume control of the draught fan with low cost, high control accuracy, fast adjustment speed and good stability is achieved.

Abstract: A method for harmonic detection includes: acquiring a ripple component of a direct-current bus voltage; acquiring a harmonic component of the direct-current bus voltage based on the ripple component; acquiring a quadrature component of the harmonic component based on the harmonic component; acquiring a characteristic parameter of the harmonic component based on the quadrature component, in which the characteristic parameter includes a phase; and acquiring and outputting a voltage amplitude of the harmonic component based on the quadrature component and the phase of the harmonic component.