中文
含义
长虹变频空调检测到 PFC（功率因数校正）电路故障，显示屏显示 F4 错误代码。PFC 电路是变频驱动板的重要组成部分，负责将交流输入电流整形为正弦波以提高功率因数，同时将直流母线电压升压至稳定水平。PFC 故障会导致母线电压不足、谐波增大，IPM 模块无法正常工作，空调触发保护停机。
常见原因
- PFC 电路中的升压电感线圈匝间短路或磁芯碎裂，电感量异常。
- PFC 开关管（IGBT 或 MOSFET）击穿或性能退化，无法正常导通和关断。
- PFC 控制 IC 内部损坏或外围电路元件故障，导致驱动信号异常。
- PFC 母线滤波电容失效或容量衰减，导致 PFC 输出不稳定。
- PFC 电流检测电阻（采样电阻）阻值漂移，导致控制系统误判 PFC 工作状态。
- 电网输入电压过低或波动过大，超出 PFC 电路正常工作范围。
自助排查
- 断开空调电源，等待 5 分钟后重新通电开机，观察 F4 是否消除。电网瞬时异常可能触发保护，正常后自动恢复。
- 使用万用表测量电源插座电压，确认电网电压在 198V–242V 的正常范围内。如果电压长期偏低（低于 190V），建议安装稳压器。
- 避免与其他大功率电器共用同一电路插座，减轻同一线路的电压波动。
- 如果家中近期出现频繁跳闸或电压不稳现象，请联系物业或电力公司检查线路。
- PFC 电路检修涉及高压直流电路和精密功率元件，非专业人员严禁拆修。请联系长虹空调售后服务中心，由专业技师使用示波器检测 PFC 驱动波形和母线电压，确定故障元件并更换室外机驱动板。
English
Meaning
The Changhong inverter air conditioner has detected a PFC (Power Factor Correction) circuit fault, displaying the F4 error code. The PFC circuit is a critical component of the inverter driver board, responsible for shaping the AC input current into a sine wave to improve the power factor while boosting the DC bus voltage to a stable level. A PFC fault results in insufficient bus voltage and increased harmonics — the IPM module cannot operate normally, and the AC triggers protection shutdown.
Common Causes
- Inter-turn short circuit or cracked magnetic core in the PFC boost inductor, causing abnormal inductance.
- The PFC switching transistor (IGBT or MOSFET) has broken down or degraded and cannot switch on and off normally.
- The PFC control IC is internally damaged or its peripheral circuit components have failed, causing abnormal drive signals.
- The PFC bus filter capacitor has failed or lost capacitance, causing unstable PFC output.
- The PFC current sensing resistor (shunt) has drifted in resistance value, causing the control system to misjudge the PFC operating state.
- The grid input voltage is too low or fluctuating excessively, beyond the PFC circuit’s normal operating range.
Self-Check Steps
- Disconnect the AC from power, wait 5 minutes, then reconnect and start. Observe whether F4 clears — transient grid anomalies may trigger protection, which self-recovers once conditions normalize.
- Use a multimeter to measure outlet voltage and confirm the grid voltage is within the normal range of 198V–242V. If the voltage is persistently low (below 190V), consider installing a voltage stabilizer.
- Avoid sharing the same circuit outlet with other high-power appliances to reduce voltage fluctuations on the same line.
- If frequent breaker tripping or unstable voltage has occurred recently in the home, contact property management or the power company to check the wiring.
- PFC circuit repair involves high-voltage DC circuits and precision power components — non-professionals are strictly prohibited from attempting disassembly. Contact Changhong AC after-sales service for a professional technician to use an oscilloscope to test PFC drive waveforms and bus voltage, identify the faulty component, and replace the outdoor unit driver board.