Bus capacitor voltage regulating circuit, frequency converter and air conditioner

The invention provides a bus capacitor voltage regulating circuit, a frequency converter and an air conditioner, a bus capacitor comprises a first capacitor and a second capacitor which are connectedin series between a positive bus and a negative bus, the bus capacitor voltage regulating circuit comprises a voltage division circuit, wherein the voltage division circuit is connected between the positive bus and the negative bus, and the voltage division circuit is used for generating voltage division voltage; and a voltage regulating circuit connected with the positive bus, the negative bus, the voltage division circuit, the first capacitor and the second capacitor, and the voltage regulating circuit is switched on or switched off according to the voltage division voltage so as to regulatethe voltage of the first capacitor or the voltage of the second capacitor. On one hand, the voltage of the first capacitor and the voltage of the second capacitor are averaged, the voltage equalizingeffect is improved, and fa