Variable-frequency air-conditioner current frequency limiting method and device

Abstract

The invention discloses a variable-frequency air-conditioner current frequency limiting method and device. A variable-frequency air-conditioner comprises a rectification circuit, a power factor correction PFC circuit and a compressor. The input end of the PFC circuit is connected with the output end of the rectification circuit. The output end of the PFC circuit is connected with the compressor. The method comprises the following steps that the input current effective value Iin_rms of the variable-frequency air-conditioner is acquired; the preset current frequency limiting threshold is subtracted from the input current effective value Iin_rms so that a current difference value of the input current effective value Iin_rms and the current frequency limiting threshold is acquired, and the current difference value is judged; if the current difference value is greater than or equal to a first threshold, the compressor is controlled to stop operation; and if the current difference value is greater than or equal to a second threshold and less than the first threshold, the compressor is controlled to perform underclocking operation according to the preset step length, wherein the second threshold is less than the first threshold so that output power is reduced by controlling operation frequency of the compressor and then an objective of reducing input current is achieved, the heating condition of an input circuit is improved and an over-current fault can be avoided.

Description

technical field [0001] The invention relates to the technical field of air conditioners, in particular to a current frequency limiting method for an inverter air conditioner and a current frequency limiting device for an inverter air conditioner. Background technique [0002] In a single-phase AC power input system such as a household air conditioner, the single-phase AC power from the grid usually passes through an uncontrollable full-bridge rectifier circuit first, then passes through a power factor correction circuit, then outputs DC and connects it to a large-capacity electrolytic capacitor, and finally provides it to Loads such as internal switching power supplies, compressors and fans, etc. [0003] In the related art, as the operating frequency of the compressor increases, the input current increases accordingly, which makes the components in the input circuit heat up severely, and may also cause an overcurrent fault and cause damage to the components. Therefore, rel...

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Problems solved by technology

[0003] In the related technology, as the operating frequency of the compressor increases, the input current increases accordingly, which makes the devices in the input circuit to heat up seriously, and may also cause overcurrent faults, resulting in damage to the devices

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