PFC circuit protection device and air conditioner

Abstract

The invention provides a PFC circuit protection device. The PFC circuit protection device can perform voltage protection and current protection simultaneously or successively. The current protection comprises first-stage current protection and second-stage current protection; and when a first-stage current protection threshold is smaller than or equal to a PFC current sampling conditioning signaland the PFC current sampling conditioning signal is smaller than a second-stage current protection threshold, the first-stage current protection is triggered, a PFC abnormal operation signal is output, an IGBT is immediately kept in a turn-off state, and after a control chip receives a corresponding signal, only the PWM output of the PFC is turned off while the whole machine is not controlled to be shut down; According to the voltage protection, an AC input voltage sampling conditioning signal is compared with a voltage protection threshold, and a PFC normal or abnormal operation signal is output according to a comparison result; and when the PFC abnormal operation signal is output, the IGBT is immediately kept in the turn-off state, and after the control chip receives the corresponding signal, only the PWM output is turned off while the whole machine is not controlled to be shut down. The invention also provides an air conditioner. According to the air conditioner, the abnormal current of the PFC can be effectively reduced, the IGBT can be quickly turned off, the damage to the IGBT is reduced, and unnecessary shutdown of the whole machine is avoided.

Description

technical field [0001] The invention belongs to the technical field of air conditioners, and in particular relates to a PFC circuit protection device and an air conditioner. Background technique [0002] In the application of air conditioners, the installation environment of the outdoor unit is complex, and problems such as surges and interference are prominent, resulting in abnormal voltage and current abnormalities in the PFC. Therefore, high requirements are placed on the reliability of the air conditioner controller. [0003] In response to the above problems, the method widely used in the industry is to add a PFC protection circuit to the controller, but the PFC protection device commonly used at present only includes the first-level current protection, which has the following defects: [0004] (1) There is only one level of current protection, and the user experience is difficult to guarantee. In the case of only the first-level current protection, in order to ensure ...

AI Technical Summary

Problems solved by technology

[0004](1) There is only one level of current protection, and the user experience is difficult to guarantee

In the case of only the first-level current protection, in order to ensure the reliability of the whole machine, the whole machine will stop when the PFC current reaches the protection threshold. There is no current limiting measure to maintain the non-stop state, which affects the user experience

[0005](2) The response time of current protection is long and slow, which will cause great damage to IGBT

Surge voltage and voltage drop are the main factors causing PFC current abnormality, but the response of the current always lags behind the voltage, so the response speed of the current protection is slower than that of the voltage protection

At the same time, the current protection needs the actual current to reach the protection threshold to respond. At this time, the current is already very large, which will cause damage to the IGBT

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