Inverter air conditioner and overcurrent protection circuit of power factor correction pfc circuit

Abstract

The invention discloses a variable frequency air conditioner and an over-current protective circuit of a power factor correction (PFC) circuit. The over-current protective circuit comprises a PFC driver, a current detection unit, a comparison unit, and a microcontroller. The PFC driver is used for driving the PFC circuit. The current detection unit is used for detecting the input current of the PFC circuit in order to acquire the instantaneous value of the complete input current of the variable frequency air conditioner. The comparison unit is used for generating an over-current protective signal according to the instantaneous value of the complete input current. The microcontroller is used for receiving the over-current protective signal, sampling the instantaneous value of the complete input current, outputting a PFC control signal to the PFC driver, and outputting a compressor control signal to a compressor driver. The PFC driver drives the PFC circuit according to the over-current protective signal and the PFC control signal. The microcontroller controls the output states of a PFC signal output end and a compressor signal output end according to the over-current protective signal and the instantaneous value of the complete input current. Accordingly, dual protection is provided for the PFC circuit in hardware and software aspects, the PFC circuit is prevented from being damaged by over-current, and system reliability is improved.

Description

technical field [0001] The invention relates to the technical field of air conditioners, in particular to an overcurrent protection circuit of a power factor correction PFC circuit in an inverter air conditioner and an inverter air conditioner. Background technique [0002] Inverter air conditioners have been widely used. In order to reduce current harmonics and improve power factor, most of the electric control boards of inverter air conditioners use active power factor correction PFC circuits. The tube is damaged. [0003] In related technologies, the following overcurrent protection strategy is usually adopted: detect the input current of the whole machine, and compare the input current of the whole machine with the current protection threshold through a hardware comparison circuit to generate an input overcurrent protection signal. When the protection threshold is reached, the driving signal of the PFC circuit and the driving signal of the compressor are turned off. Ho...

AI Technical Summary

Problems solved by technology

However, its disadvantages are that the charging current of the electrolytic capacitor is likely to cause false protection, and the overcurrent protection cannot be realized when the hardware comparison circuit fails.

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